KVM/arm64 fixes for 7.2, take #3
- Fix a tiny buglet when propagating the deactivation of an interrupt
from a nested guest, which happened to trigger a gold plated CPU bug
on a particular implementation
- Fix a race between LPI unmapping and mapping, resulting in leaked
LPIs
- Make LPI mapping more robust on memory allocation failure
- Fix the handling of the EL2 tracing clock being disabled
- A couple of Sashiko-driven fixes for corner cases in the EL2 tracing
code
- Add missing sysreg tracepoint for the EL2 code
- Tidy-up the mutual exclusion of guest-memfd and MTE
- Update Fuad's email address to point to @linux.dev
FOLL_LONGTERM pinning fails for some memory types, such as file-backed
guest memory. As a result, kvm_s390_adapter_map() returns -EINVAL and
irqfd adapter registration fails even though interrupt delivery could
still work via the existing non-atomic path.
When FOLL_LONGTERM pinning fails, verify that the page is accessible
using a short-term pin instead. If the short-term pin succeeds, unpin
the page and add a map entry with pinned=false to preserve MAP/UNMAP
symmetry. The non-atomic irqfd path already performs short-term pinning
for interrupt delivery, so this restores the previous behavior for
memory that cannot be pinned long-term.
get_map_info() is updated to return NULL for unpinned entries so that
the atomic irqfd fast path falls back to the non-atomic path.
kvm_s390_adapter_unmap() and kvm_s390_unmap_all_adapters() skip dirty
marking and unpin for unpinned entries.
Update Documentation/virt/kvm/devices/s390_flic.rst to reflect the
new MAP/UNMAP behavior.
Fixes: c9a5688380 ("KVM: s390: Add map/unmap ioctl and clean mappings post-guest")
Signed-off-by: Jaehoon Kim <jhkim@linux.ibm.com>
Reviewed-by: Douglas Freimuth <freimuth@linux.ibm.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Signed-off-by: Christian Borntraeger <borntraeger@linux.ibm.com>
The user cannot use MTE on VMAs created by mapping a guest_memfd file,
as arch_calc_vm_flag_bits() does not set VM_MTE_ALLOWED.
When creating a guest_memfd backed memslot,
kvm_arch_prepare_memory_region() rejects the memslot if MTE is enabled for
the VM and if guest_memfd has been mapped in a VMA that intersects the
memslot.
However, the documentation for KVM_SET_USER_MEMORY_REGION2 explicitly
states that the only condition for userspace_addr is for it to be a legal
userspace address, but the mapping is not required to be valid nor
populated at memslot creation.
If userspace sets userspace_addr to an address that hasn't been mapped, or
if userspace_addr belongs to a VMA that isn't backed by the guest_memfd
file, or if the VMA doesn't intersect the memslot, memslot creation is
successful and KVM ends up with a VM with MTE and guest_memfd-backed
memslots.
The same happens if the order is reversed: when userspace enables MTE, KVM
does not check if memslots backed by guest_memfd are already present.
Fix both issues by rejecting guest_memfd-backed memslots when MTE is
enabled, and by rejecting MTE when guest_memfd-backed memslots are already
present.
Fixes: 32e200bd6e ("KVM: arm64: Enable support for guest_memfd backed memory")
Tested-by: Fuad Tabba <fuad.tabba@linux.dev>
Reviewed-by: Fuad Tabba <fuad.tabba@linux.dev>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Link: https://patch.msgid.link/20260722090354.94245-1-alexandru.elisei@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Pull kvm fixes from Paolo Bonzini:
"s390:
- Fix S390_USER_OPEREXEC so it can now be enabled regardless of other
unrelated capabilities
- Fix handling of the _PAGE_UNUSED pte bit that could lead to guest
memory corruption in some scenarios
- A bunch of misc gmap fixes (locking, behaviour under memory
pressure)
- Fix CMMA dirty tracking
x86:
- Tidy up some WARN_ON() and BUG_ON(), replacing them with
WARN_ON_ONCE() or KVM_BUG_ON(). All of these have obviously never
triggered, or somebody would have been annoyed earlier, but still...
- Fix missing interrupt due to stale CR8 intercept
- Add a statistic that can come in handy to debug leaks as well as
the vulnerability to a class of recently-discovered issues
- Do not ask arch/x86/kernel to export
default_cpu_present_to_apicid() just for KVM"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (22 commits)
x86/apic: KVM: Use cpu_physical_id() to get APIC ID of running vCPU for AVIC
KVM: x86/mmu: Expose number of shadow MMU shadow pages as a stat
KVM: x86: Unconditionally recompute CR8 intercept on PPR update
KVM: VMX: Grab vmcs12 on CR8 interception update iff vCPU is in guest mode
KVM: x86: WARN (once) if RTC pending EOI tracking goes off the rails
KVM: x86: WARN and fail kvm_set_irq() if a PIC or I/O APIC vector is invalid
KVM: x86: Bug the VM, not the kernel, if the ISR count {under,over}flows
KVM: x86/mmu: Bug the VM, not the host kernel, if KVM write-protects upper SPTEs
KVM: x86: Replace BUG_ON() with WARN_ON_ONCE() on "bad" nested GPA translation
KVM: Replace guest-triggerable BUG_ON() in ioeventfd datamatch with get_unaligned()
KVM: s390: Return failure in case of failure in kvm_s390_set_cmma_bits()
KVM: s390: selftests: Fix cmma selftest
KVM: s390: Fix cmma dirty tracking
KVM: s390: Fix locking in kvm_s390_set_mem_control()
KVM: s390: Fix handle_{sske,pfmf} under memory pressure
KVM: s390: Fix code typo in gmap_protect_asce_top_level()
KVM: s390: Do not set special large pages dirty
KVM: s390: Fix dat_peek_cmma() overflow
s390/mm: Fix handling of _PAGE_UNUSED pte bit
KVM: s390: Fix typo in UCONTROL documentation
...
* Fix S390_USER_OPEREXEC so it can now be enabled regardless of other
unrelated capabilities
* Fix handling of the _PAGE_UNUSED pte bit that could lead to guest
memory corruption in some scenarios
* A bunch of misc gmap fixes (locking, behaviour under memory pressure)
* Fix CMMA dirty tracking
Pull kvm updates from Paolo Bonzini:
"arm64:
This is a bit of an odd merge window on the KVM/arm64 front. There
is absolutely no new feature in the pull request. It is purely
fixes, because it is simply becoming too hard to review new stuff
when so many AI-fuelled fixes hit the list.
- Significant cleanup of the vgic-v5 PPI support which was merged in
7.1. This makes the code more maintainable, and squashes a couple
of bugs in the meantime
- Set of fixes for the handling of the MMU in an NV context,
particularly VNCR-triggered faults. S1POE support is fixed as well
- Large set of pKVM fixes, mostly addressing recurring issues around
hypervisor tracking of donated pages in obscure cases where the
donation could fail and leave things in a bizarre state
- Fixes for the so-called "lazy vgic init", which resulted in
sleeping operations in non-preemptible sections. This turned out to
be far more invasive than initially expected..
- Reduce the overhead of L1/L2 context switch by not touching the FP
registers
- Fix the way non-implemented page sizes are dealt with when a guest
insist on using them for S2 translation
- The usual set of low-impact fixes and cleanups all over the map
Loongarch:
- On a request for lazy FPU load, load all FPU state that the VM
supports instead of enabling only the part (FPU, LSX or LASX) that
caused the FPU load request
- Some enhancements about interrupt injection
- Some bug fixes and other small changes
RISC-V:
- Batch G-stage TLB flushes for GPA range based page table updates
- Convert HGEI line management to fully per-HART
- Fix missing CSR dirty marking when FWFT state updated via ONE_REG
- Fix stale FWFT feature exposure to Guest/VM
- Speed up dirty logging write faults using MMU rwlock and atomic PTE
updates using cmpxchg() for permission-only changes
- Use flexible array for APLIC IRQ state
- Use kvm_slot_dirty_track_enabled() for logging enable check on a
memslot
- Avoid skipping valid pages in kvm_riscv_gstage_wp_range()
- Avoid skipping valid pages in kvm_riscv_gstage_unmap_range()
- Use endian-specific __lelong for NACL shared memory
S390:
- KVM_PRE_FAULT_MEMORY support
- Support for 2G hugepages
- Support for the ASTFLEIE 2 facility
- Support for fast inject using kvm_arch_set_irq_inatomic
- Fix potential leak of uninitialized bytes
- A few more misc gmap fixes
x86:
- Generic support for the more granular permissions allowed by EPT,
namely "read" (which was previously usurping the U bit) and
separate execution bits for kernel and userspace
- Do not assume that all page tables start with U=1/W=1/NX=0 at the
root, as AMD GMET needs to have U=0 at the root
- Introduce common assembly macros for use within Intel and AMD
vendor-specific vmentry code. This touches the SPEC_CTRL handling,
which is now entirely done in assembly for Intel (by reusing the
AMD code that already existed), and register save/restore which
uses some macro magic to compute the offsets in the struct. Both of
these are preparatory changes for upcoming APX support
- Clean up KVM's register tracking and storage, primarily to prepare
for APX support, which expands the maximum number of GPRs from 16
to 32
- Keep a single copy of the PDPTRs rather than two, since
architecturally there is just one
- Handle EXIT_FASTPATH_EXIT_USERSPACE in vendor code to ensure vendor
code gets a chance to handle things like reaping the PML buffer
- Update KVM's view of PV async enabling if and only if the MSR write
fully succeeds
- Fix a variety of issues where the emulator doesn't honor
guest-debug state, and clean up related code along the way
- Synthesize EPT Violation and #NPF "error code" bits when injecting
faults into L1 that didn't originate in hardware (in which case the
VMCS/VMCB doesn't hold relevant information)
- Add support for virtualizing (well, emulating) AMD's flavor of
CPL>0 CPUID faulting
- Clean up the GPR APIs so that KVM's use of "raw" is consistent, and
fix a variety of minor bugs along the way
- Fix an OOB memory access due to not checking the VP ID when
handling a Hyper-V PV TLB flush for L2
- Fix a bug in the mediated PMU's handling of fixed counters that
allowed the guest to bypass the PMU event filter
- Allow userspace to return EAGAIN when handling SNP and TDX
hypercalls, so the KVM can forward a "retry" status code to the
guest, and reserve all unused error codes for future usage
- Overhaul the TDP MMU => S-EPT code to move as much S-EPT specific
logic as possible into the TDX code, and to funnel (almost) all
S-EPT updates into a single chokepoint. The motivation is largely
to prepare for upcoming Dynamic PAMT support, but the cleanups are
nice to have on their own
- Plug a hole in shadow page table handling, where KVM fails to
recursively zap nested EPT/NPT shadow page tables when the nested
hypervisor tears down its own EPT/NPT page tables from the bottom
up
x86 (Intel):
- Support for nested MBEC (Mode-Based Execute Control), see above in
the generic section; also run with MBEC enabled even for non-nested
mode
- Use the kernel's "enum pg_level" in the TDX APIs instead of the
TDX-Module's level definitions (which are 0-based)
- Rework the TDX memory APIs to not require/assume that guest memory
is backed by "struct page" (in prepartion for guest_memfd hugepage
support)
- Fix a largely benign bug where KVM TDX would incorrectly state it
could emulate several x2APIC MSRs
- Use the "safe" WRMSR API when proxying LBR MSR writes as the
to-be-written value is guest controlled and completely unvalidated
x86 (AMD):
- Support for nested GMET (Guest Mode Execution Trap), see above in
the generic section; also run with GMET enabled even for non-nested
mode
- Fixes and minor cleanups to GHCB handling, on top of the earlier
work already merged into 7.1-rc
- Ensure KVM's copy of CR0 and CR3 are up-to-date prior to invoking
fastpath handlers
- Add support for virtualizing gPAT (KVM previously just used L1's
PAT when running L2)
- Fix goofs where KVM mishandles side effects (e.g. single-step and
PMC updates) when emulating VMRUN
- Fix a variety of bugs in AVIC's handling of x2APIC MSR
interception, most notably where KVM didn't disable interception of
IRR, ISR, and TMR regs
- Add support for virtualizing Host-Only/Guest-Only bits in the
mediated PMU
- Don't advertise support for unusable VM types, and account for VM
types that are disabled by firmware, e.g. to mitigate security
vulnerabilities
- Rewrite the SEV {en,de}crypt debug ioctls as they were riddle with
bugs and unnecessarily complicated, and add comprehensive tests
- Clean up and deduplicate the SEV page pinning code
- Fix minor goofs related to writing back CPUID information after
firmware rejects a CPUID page for an SNP vCPU
Generic:
- Rename invalidate_begin() to invalidate_start() throughout KVM to
follow the kernel's nomenclature, e.g. for mmu_notifiers
- Use guard() to cleanup up various KVM+VFIO flows
- Minor cleanups
guest_memfd:
- Return -EEXIST instead of -EINVAL if userspace attempts to bind a
gmem range to multiple memslots, and fix the test that was supposed
to ensure KVM returns -EEXIST
- Treat memslot binding offsets and sizes as unsigned values to fix a
bug where KVM interprets a large "offset + size" as a negative
value and allows a nonsensical offset
- Use the inode number instead of the page offset for the NUMA
interleaving index to fix a bug where the effective index would
jump by two for consecutive pages (the caller also adds in the page
offset)
Selftests:
- Randomize the dirty log test's delay when reaping the bitmap on the
first pass, as always waiting only 1ms hid a KVM RISC-V bug as the
test reaped the bitmap before KVM could build up enough state to
hit the bug
- A pile of one-off fixes and cleanups"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (326 commits)
KVM: x86/mmu: Ensure hugepage is in by slot before checking max mapping level
KVM: x86: Fix shadow paging use-after-free due to unexpected role
KVM: s390: Introducing kvm_arch_set_irq_inatomic fast inject
KVM: s390: Enable adapter_indicators_set to use mapped pages
KVM: s390: Add map/unmap ioctl and clean mappings post-guest
riscv: kvm: Use endian-specific __lelong for NACL shared memory
KVM: selftests: access_tracking_perf_test: bump number of NUMA nodes to 32
KVM: s390: vsie: Implement ASTFLEIE facility 2
KVM: s390: vsie: Refactor handle_stfle
s390/sclp: Detect ASTFLEIE 2 facility
KVM: s390: Minor refactor of base/ext facility lists
KVM: x86/mmu: move pdptrs out of the MMU
KVM: x86: check that kvm_handle_invpcid is only invoked with shadow paging
KVM: nSVM: invalidate cached PDPTRs across nested NPT transitions
KVM: nVMX: remove unnecessary code in prepare_vmcs02_rare
KVM: x86: remove nested_mmu from mmu_is_nested()
KVM: arm64: vgic-its: Make ABI commit helpers return void
KVM: s390: Initialize KVM_S390_GET_CMMA_BITS memory
LoongArch: KVM: Add missing slots_lock for device register/unregister
LoongArch: KVM: Validate irqchip index in irqfd routing
...
Pull documentation updates from Jonathan Corbet:
"Things have calmed down a bit on the docs front, with no earthshaking
changes this time around:
- Ongoing work on the Japanese and Portuguese translations
- Better integration of the MAINTAINERS file into the rendered
documents, including a search interface
- A seemingly infinite supply of fixes for typos, minor grammatical
issues, and related problems that LLMs find with abandon"
* tag 'docs-7.2' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (93 commits)
docs: pt_BR: Translate 3.Early-stage.rst into Portuguese
docs: pt_BR: update "Purpose of Defconfigs" section in maintainer-soc.rst
Documentation: bug-hunting.rst: fix grammar
docs/ja_JP: translate submitting-patches.rst (interleaved-replies)
docs: Fix minor grammatical error
docs/{it_it,sp_SP,zh_CN,zh_TW}: update references to removed CONFIG_DEBUG_SLAB
Documentation: process: fix brackets
Documentation: arch: fix brackets
docs/dyndbg: explain flags parse 1st
docs/dyndbg: update examples \012 to \n
docs: kernel-parameters: Fix stale sticore file paths
docs: real-time: Fix duplicated sched(7) text
docs: kgdb: Fix stale source file paths
docs: sonypi: Fix stale header file path
docs: kernel-parameters: Remove sa1100ir IrDA parameter
iommu: Documentation: rearrange, update kernel-parameters
docs: md: fix grammar in speed_limit description
docs: changes.rst: restore pahole 1.26 minimum (regressed by sort)
Documentation: Fix syntax of kmalloc_objs example in coding style doc
docs: pt_BR: update maintainer-handbooks
...
KVM: s390: New features for 7.2
New features for 7.2 for KVM/s390:
* KVM_PRE_FAULT_MEMORY support
* Support for 2G hugepages
* Support for the ASTFLEIE 2 facility
* kvm_arch_set_irq_inatomic Fast Inject
* Fix potential leak of uninitialized bytes
KVM/arm64 updates for 7.2
* New features:
- None. Zilch. Nada. Que dalle.
* Fixes and other improvements:
- Significant cleanup of the vgic-v5 PPI support which was merged in
7.1. This makes the code more maintainable, and squashes a couple
of bugs in the meantime.
- Set of fixes for the handling of the MMU in an NV context,
particularly VNCR-triggered faults. S1POE support is fixed
as well.
- Large set of pKVM fixes, mostly addressing recurring issues
around hypervisor tracking of donated pages in obscure cases
where the donation could fail and leave things in a bizarre
state.
- Fixes for the so-called "lazy vgic init", which resulted in
sleeping operations in non-preemptible sections. This turned
out to be far more invasive than initially expected...
- Reduce the overhead of L1/L2 context switch by not touching
the FP registers.
- Fix the way non-implemented page sizes are dealt with when
a guest insist on using them for S2 translation.
- The usual set of low-impact fixes and cleanups all over the map.
KVM SVM changes for 7.2
- Add support for virtualizing gPAT (KVM previously just used L1's PAT when
running L2).
- Fix goofs where KVM mishandles side effects (e.g. single-step and PMC
updates) when emulating VMRUN.
- Fix a variety of bugs in AVIC's handling of x2APIC MSR interception, most
notably where KVM didn't disable interception of IRR, ISR, and TMR regs.
- Add support for virtualizing Host-Only/Guest-Only bits in the mediated PMU.
KVM misc x86 changes for 7.2
- Handle EXIT_FASTPATH_EXIT_USERSPACE in vendor code to ensure vendor code
gets a chance to handle things like reaping the PML buffer.
- Ensure KVM's copy of CR0 and CR3 are up-to-date on SVM prior to invoking
fastpath handlers.
- Update KVM's view of PV async enabling if and only if the MSR write fully
succeeds.
- Fix a variety of issues where the emulator doesn't honor guest-debug state,
and clean up related code along the way.
- Synthesize EPT Violation and #NPF "error code" bits when injecting faults
into L1 that didn't originate in hardware (in which case the VMCS/VMCB
doesn't hold relevant information).
- Add support for virtualizing (well, emulating) AMD's flavor of CPL>0 CPUID
faulting.
- Clean up the GPR APIs so that KVM's use of "raw" is consistent, and fix a
variety of minor bugs along the way.
- Fix an OOB memory access due to not checking the VP ID when handling a
Hyper-V PV TLB flush for L2.
- Fix a bug in the mediated PMU's handling of fixed counters that allowed the
guest to bypass the PMU event filter.
- Allow userspace to return EAGAIN when handling SNP and TDX hypercalls, so
the KVM can forward a "retry" status code to the guest, and reserve all
unused error codes for future usage.
- Misc fixes and cleanups.
* kvm-arm64/vgic-v5-PPI-fixes:
: .
: Substantial cleanup of the vgic-v5 PPI support. From the original
: cover letter:
:
: "With the GICv5 PPi support merged in, it has become obvious that a few
: things could be improved, both from the correctness and maintainability
: angles."
: .
KVM: arm64: Fix arch timer interrupts for GICv3-on-GICv5 guests
irqchip/gic-v5: Immediately exec priority drop following activate
Documentation: KVM: Clarify that PMU_V3_IRQ IntID requirements for GICv5
Documentation: KVM: Fix typos in VGICv5 documentation
KVM: arm64: selftests: Improve error handling for GICv5 PPI selftest
KVM: arm64: selftests: Cleanup unused vars in GICv5 PPI selftest
KVM: arm64: selftests: Add missing GIC CDEN to no-vgic-v5 selftest
KVM: arm64: vgic-v5: Atomically assign bits to PPI DVI bitmap
KVM: arm64: vgic-v5: Add missing trap handing for NV triage
KVM: arm64: vgic-v5: Limit support to 64 PPIs
KVM: arm64: vgic: Rationalise per-CPU irq accessor
KVM: arm64: vgic-v5: Drop defensive checks from vgic_v5_ppi_queue_irq_unlock()
KVM: arm64: vgic: Consolidate vgic_allocate_private_irqs_locked()
KVM: arm64: vgic: Constify struct irq_ops usage
KVM: arm64: vgic-v5: Drop pointless ARM64_HAS_GICV5_CPUIF check
KVM: arm64: vgic-v5: Remove use of __assign_bit() with a constant
KVM: arm64: vgic-v5: Move PPI caps into kvm_vgic_global_state
KVM: arm64: vgic-v5: Add for_each_visible_v5_ppi() iterator
Signed-off-by: Marc Zyngier <maz@kernel.org>
MAPGPA request from TDX VMs gets split into chunks by KVM using a loop
of userspace exits until the complete range is handled.
In some cases userspace VMM might decide to break the MAPGPA operation
and continue it later. For example: in the case of intrahost migration
userspace might decide to continue the MAPGPA operation after the
migration is completed.
Allow userspace to signal to TDX guests that the MAPGPA operation should
be retried the next time the guest is scheduled.
This is potentially a breaking change since if userspace sets
hypercall.ret to a value other than EBUSY or EINVAL an EINVAL error code
will be returned to userspace. As of now QEMU never sets hypercall.ret
to a non-zero value after handling KVM_EXIT_HYPERCALL so this change
should be safe.
Reviewed-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Vishal Annapurve <vannapurve@google.com>
Co-developed-by: Sagi Shahar <sagis@google.com>
Signed-off-by: Sagi Shahar <sagis@google.com>
Link: https://patch.msgid.link/20260305222627.4193305-2-sagis@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Add a 'gpat' field to kvm_svm_nested_state_hdr to carry L2's guest PAT
value across save and restore.
When KVM_X86_QUIRK_NESTED_SVM_SHARED_PAT is disabled and the vCPU is in
guest mode with nested NPT enabled, save vmcb02's g_pat into the header on
KVM_GET_NESTED_STATE, and restore it on KVM_SET_NESTED_STATE.
Host-initiated accesses to IA32_PAT (via KVM_GET/SET_MSRS) always target
L1's hPAT, so they cannot be used to save or restore gPAT. The separate
header field ensures that KVM_GET/SET_MSRS and KVM_GET/SET_NESTED_STATE are
independent and can be ordered arbitrarily during save and restore.
Note that struct kvm_svm_nested_state_hdr is included in a union padded to
120 bytes, so there is room to add the gpat field without changing any
offsets.
Fixes: cc440cdad5 ("KVM: nSVM: implement KVM_GET_NESTED_STATE and KVM_SET_NESTED_STATE")
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://patch.msgid.link/20260407190343.325299-9-jmattson@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Define a quirk to control whether nested SVM shares L1's PAT with L2
(legacy behavior) or gives L2 its own independent gPAT (correct behavior
per the APM).
When the quirk is enabled (default), L2 shares L1's PAT, preserving the
legacy KVM behavior. When userspace disables the quirk, KVM correctly
virtualizes the PAT for nested SVM guests, giving L2 a separate gPAT as
specified in the AMD architecture.
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://patch.msgid.link/20260407190343.325299-2-jmattson@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Guest page tables can be reused independent of the value of CR4.SMEP
(at least if WP=1). However, this is not true of EPT MBEC pages,
because presence of EPT entries is signaled by bits 0-2 when MBEC
is off, and bits 0-2 + bit 10 when MBEC is on.
In preparation for enabling MBEC, move cr4_smep to the base role.
This makes the smep_andnot_wp bit redundant, so remove it.
Tested-by: David Riley <d.riley@proxmox.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
* kvm-arm64/pkvm-protected-guest: (41 commits)
: .
: pKVM support for protected guests, implementing the very long
: awaited support for anonymous memory, as the elusive guestmem
: has failed to deliver on its promises despite a multi-year
: effort. Patches courtesy of Will Deacon. From the initial cover
: letter:
:
: "[...] this patch series implements support for protected guest
: memory with pKVM, where pages are unmapped from the host as they are
: faulted into the guest and can be shared back from the guest using pKVM
: hypercalls. Protected guests are created using a new machine type
: identifier and can be booted to a shell using the kvmtool patches
: available at [2], which finally means that we are able to test the pVM
: logic in pKVM. Since this is an incremental step towards full isolation
: from the host (for example, the CPU register state and DMA accesses are
: not yet isolated), creating a pVM requires a developer Kconfig option to
: be enabled in addition to booting with 'kvm-arm.mode=protected' and
: results in a kernel taint."
: .
KVM: arm64: Don't hold 'vm_table_lock' across guest page reclaim
KVM: arm64: Allow get_pkvm_hyp_vm() to take a reference to a dying VM
KVM: arm64: Prevent teardown finalisation of referenced 'hyp_vm'
drivers/virt: pkvm: Add Kconfig dependency on DMA_RESTRICTED_POOL
KVM: arm64: Rename PKVM_PAGE_STATE_MASK
KVM: arm64: Extend pKVM page ownership selftests to cover guest hvcs
KVM: arm64: Extend pKVM page ownership selftests to cover forced reclaim
KVM: arm64: Register 'selftest_vm' in the VM table
KVM: arm64: Extend pKVM page ownership selftests to cover guest donation
KVM: arm64: Add some initial documentation for pKVM
KVM: arm64: Allow userspace to create protected VMs when pKVM is enabled
KVM: arm64: Implement the MEM_UNSHARE hypercall for protected VMs
KVM: arm64: Implement the MEM_SHARE hypercall for protected VMs
KVM: arm64: Add hvc handler at EL2 for hypercalls from protected VMs
KVM: arm64: Return -EFAULT from VCPU_RUN on access to a poisoned pte
KVM: arm64: Reclaim faulting page from pKVM in spurious fault handler
KVM: arm64: Introduce hypercall to force reclaim of a protected page
KVM: arm64: Annotate guest donations with handle and gfn in host stage-2
KVM: arm64: Change 'pkvm_handle_t' to u16
KVM: arm64: Introduce host_stage2_set_owner_metadata_locked()
...
Signed-off-by: Marc Zyngier <maz@kernel.org>
Now that all the bits are properly addressed, provide a mechanism
for testing ESA mode guests in nested configurations.
Signed-off-by: Hendrik Brueckner <brueckner@linux.ibm.com>
[farman@us.ibm.com: Updated commit message]
Reviewed-by: Janosch Frank <frankja@linux.ibm.com>
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Signed-off-by: Janosch Frank <frankja@linux.ibm.com>
GICv5 systems will likely not support the full set of PPIs. The
presence of any virtual PPI is tied to the presence of the physical
PPI. Therefore, the available PPIs will be limited by the physical
host. Userspace cannot drive any PPIs that are not implemented.
Moreover, it is not desirable to expose all PPIs to the guest in the
first place, even if they are supported in hardware. Some devices,
such as the arch timer, are implemented in KVM, and hence those PPIs
shouldn't be driven by userspace, either.
Provided a new UAPI:
KVM_DEV_ARM_VGIC_GRP_CTRL => KVM_DEV_ARM_VGIC_USERPSPACE_PPIs
This allows userspace to query which PPIs it is able to drive via
KVM_IRQ_LINE.
Additionally, introduce a check in kvm_vm_ioctl_irq_line() to reject
any PPIs not in the userspace mask.
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20260319154937.3619520-40-sascha.bischoff@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Make it mandatory to use the architected PPI when running a GICv5
guest. Attempts to set anything other than the architected PPI (23)
are rejected.
Additionally, KVM_ARM_VCPU_PMU_V3_INIT is relaxed to no longer require
KVM_ARM_VCPU_PMU_V3_IRQ to be called for GICv5-based guests. In this
case, the architectued PPI is automatically used.
Documentation is bumped accordingly.
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Link: https://patch.msgid.link/20260319154937.3619520-33-sascha.bischoff@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
Interrupts under GICv5 look quite different to those from older Arm
GICs. Specifically, the type is encoded in the top bits of the
interrupt ID.
Extend KVM_IRQ_LINE to cope with GICv5 PPIs and SPIs. The requires
subtly changing the KVM_IRQ_LINE API for GICv5 guests. For older Arm
GICs, PPIs had to be in the range of 16-31, and SPIs had to be
32-1019, but this no longer holds true for GICv5. Instead, for a GICv5
guest support PPIs in the range of 0-127, and SPIs in the range
0-65535. The documentation is updated accordingly.
The SPI range doesn't cover the full SPI range that a GICv5 system can
potentially cope with (GICv5 provides up to 24-bits of SPI ID space,
and we only have 16 bits to work with in KVM_IRQ_LINE). However, 65k
SPIs is more than would be reasonably expected on systems for years to
come.
In order to use vgic_is_v5(), the kvm/arm_vgic.h header is added to
kvm/arm.c.
Note: As the GICv5 KVM implementation currently doesn't support
injecting SPIs attempts to do so will fail. This restriction will by
lifted as the GICv5 KVM support evolves.
Co-authored-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Timothy Hayes <timothy.hayes@arm.com>
Signed-off-by: Sascha Bischoff <sascha.bischoff@arm.com>
Reviewed-by: Jonathan Cameron <jonathan.cameron@huawei.com>
Link: https://patch.msgid.link/20260319154937.3619520-28-sascha.bischoff@arm.com
Signed-off-by: Marc Zyngier <maz@kernel.org>
A recently added quirk does not fit in the left column of the table,
so it all has to be reformatted and realigned.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add KVM_X86_QUIRK_VMCS12_ALLOW_FREEZE_IN_SMM to allow L1 to set
FREEZE_IN_SMM in vmcs12's GUEST_IA32_DEBUGCTL field, as permitted
prior to commit 6b1dd26544 ("KVM: VMX: Preserve host's
DEBUGCTLMSR_FREEZE_IN_SMM while running the guest"). Enable the quirk
by default for backwards compatibility (like all quirks); userspace
can disable it via KVM_CAP_DISABLE_QUIRKS2 for consistency with the
constraints on WRMSR(IA32_DEBUGCTL).
Note that the quirk only bypasses the consistency check. The vmcs02 bit is
still owned by the host, and PMCs are not frozen during virtualized SMM.
In particular, if a host administrator decides that PMCs should not be
frozen during physical SMM, then L1 has no say in the matter.
Fixes: 095686e6fc ("KVM: nVMX: Check vmcs12->guest_ia32_debugctl on nested VM-Enter")
Cc: stable@vger.kernel.org
Signed-off-by: Jim Mattson <jmattson@google.com>
Link: https://patch.msgid.link/20260205231537.1278753-1-jmattson@google.com
[sean: tag for stable@, clean-up and fix goofs in the comment and docs]
Signed-off-by: Sean Christopherson <seanjc@google.com>
[Rename quirk. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
KVM generic changes for 7.0
- Remove a subtle pseudo-overlay of kvm_stats_desc, which, aside from being
unnecessary and confusing, triggered compiler warnings due to
-Wflex-array-member-not-at-end.
- Document that vcpu->mutex is take outside of kvm->slots_lock and
kvm->slots_arch_lock, which is intentional and desirable despite being
rather unintuitive.
Explicitly document the ordering of vcpu->mutex being taken *outside* of
kvm->slots_lock. While somewhat unintuitive since vCPUs conceptually have
narrower scope than VMs, the scope of the owning object (vCPU versus VM)
doesn't automatically carry over to the lock. In this case, vcpu->mutex
has far broader scope than kvm->slots_lock. As Paolo put it, it's a
"don't worry about multiple ioctls at the same time" mutex that's intended
to be taken at the outer edges of KVM.
More importantly, arm64 and x86 have gained flows that take kvm->slots_lock
inside of vcpu->mutex. x86's kvm_inhibit_apic_access_page() is particularly
nasty, as slots_lock is taken quite deep within KVM_RUN, i.e. simply
swapping the ordering isn't an option.
Commit to the vcpu->mutex => kvm->slots_lock ordering, as vcpu->mutex
really is intended to be a "top-level" lock, whereas kvm->slots_lock is
"just" a helper lock.
Opportunistically document that vcpu->mutex is also taken outside of
slots_arch_lock, e.g. when allocating shadow roots on x86 (which is the
entire reason slots_arch_lock exists, as shadow roots must be allocated
while holding kvm->srcu)
kvm_mmu_new_pgd()
|
-> kvm_mmu_reload()
|
-> kvm_mmu_load()
|
-> mmu_alloc_shadow_roots()
|
-> mmu_first_shadow_root_alloc()
but also when manipulating memslots in vCPU context, e.g. when inhibiting
the APIC-access page via the aforementioned kvm_inhibit_apic_access_page()
kvm_inhibit_apic_access_page()
|
-> __x86_set_memory_region()
|
-> kvm_set_internal_memslot()
|
-> kvm_set_memory_region()
|
-> kvm_set_memslot()
Cc: Oliver Upton <oliver.upton@linux.dev>
Cc: Marc Zyngier <maz@kernel.org>
Link: https://patch.msgid.link/20260302170239.596810-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
KVM_CAP_SYNC_MMU is provided by KVM's MMU notifiers, which are now always
available. Move the definition from individual architectures to common
code.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Pull KVM updates from Paolo Bonzini:
"Loongarch:
- Add more CPUCFG mask bits
- Improve feature detection
- Add lazy load support for FPU and binary translation (LBT) register
state
- Fix return value for memory reads from and writes to in-kernel
devices
- Add support for detecting preemption from within a guest
- Add KVM steal time test case to tools/selftests
ARM:
- Add support for FEAT_IDST, allowing ID registers that are not
implemented to be reported as a normal trap rather than as an UNDEF
exception
- Add sanitisation of the VTCR_EL2 register, fixing a number of
UXN/PXN/XN bugs in the process
- Full handling of RESx bits, instead of only RES0, and resulting in
SCTLR_EL2 being added to the list of sanitised registers
- More pKVM fixes for features that are not supposed to be exposed to
guests
- Make sure that MTE being disabled on the pKVM host doesn't give it
the ability to attack the hypervisor
- Allow pKVM's host stage-2 mappings to use the Force Write Back
version of the memory attributes by using the "pass-through'
encoding
- Fix trapping of ICC_DIR_EL1 on GICv5 hosts emulating GICv3 for the
guest
- Preliminary work for guest GICv5 support
- A bunch of debugfs fixes, removing pointless custom iterators
stored in guest data structures
- A small set of FPSIMD cleanups
- Selftest fixes addressing the incorrect alignment of page
allocation
- Other assorted low-impact fixes and spelling fixes
RISC-V:
- Fixes for issues discoverd by KVM API fuzzing in
kvm_riscv_aia_imsic_has_attr(), kvm_riscv_aia_imsic_rw_attr(), and
kvm_riscv_vcpu_aia_imsic_update()
- Allow Zalasr, Zilsd and Zclsd extensions for Guest/VM
- Transparent huge page support for hypervisor page tables
- Adjust the number of available guest irq files based on MMIO
register sizes found in the device tree or the ACPI tables
- Add RISC-V specific paging modes to KVM selftests
- Detect paging mode at runtime for selftests
s390:
- Performance improvement for vSIE (aka nested virtualization)
- Completely new memory management. s390 was a special snowflake that
enlisted help from the architecture's page table management to
build hypervisor page tables, in particular enabling sharing the
last level of page tables. This however was a lot of code (~3K
lines) in order to support KVM, and also blocked several features.
The biggest advantages is that the page size of userspace is
completely independent of the page size used by the guest:
userspace can mix normal pages, THPs and hugetlbfs as it sees fit,
and in fact transparent hugepages were not possible before. It's
also now possible to have nested guests and guests with huge pages
running on the same host
- Maintainership change for s390 vfio-pci
- Small quality of life improvement for protected guests
x86:
- Add support for giving the guest full ownership of PMU hardware
(contexted switched around the fastpath run loop) and allowing
direct access to data MSRs and PMCs (restricted by the vPMU model).
KVM still intercepts access to control registers, e.g. to enforce
event filtering and to prevent the guest from profiling sensitive
host state. This is more accurate, since it has no risk of
contention and thus dropped events, and also has significantly less
overhead.
For more information, see the commit message for merge commit
bf2c3138ae ("Merge tag 'kvm-x86-pmu-6.20' ...")
- Disallow changing the virtual CPU model if L2 is active, for all
the same reasons KVM disallows change the model after the first
KVM_RUN
- Fix a bug where KVM would incorrectly reject host accesses to PV
MSRs when running with KVM_CAP_ENFORCE_PV_FEATURE_CPUID enabled,
even if those were advertised as supported to userspace,
- Fix a bug with protected guest state (SEV-ES/SNP and TDX) VMs,
where KVM would attempt to read CR3 configuring an async #PF entry
- Fail the build if EXPORT_SYMBOL_GPL or EXPORT_SYMBOL is used in KVM
(for x86 only) to enforce usage of EXPORT_SYMBOL_FOR_KVM_INTERNAL.
Only a few exports that are intended for external usage, and those
are allowed explicitly
- When checking nested events after a vCPU is unblocked, ignore
-EBUSY instead of WARNing. Userspace can sometimes put the vCPU
into what should be an impossible state, and spurious exit to
userspace on -EBUSY does not really do anything to solve the issue
- Also throw in the towel and drop the WARN on INIT/SIPI being
blocked when vCPU is in Wait-For-SIPI, which also resulted in
playing whack-a-mole with syzkaller stuffing architecturally
impossible states into KVM
- Add support for new Intel instructions that don't require anything
beyond enumerating feature flags to userspace
- Grab SRCU when reading PDPTRs in KVM_GET_SREGS2
- Add WARNs to guard against modifying KVM's CPU caps outside of the
intended setup flow, as nested VMX in particular is sensitive to
unexpected changes in KVM's golden configuration
- Add a quirk to allow userspace to opt-in to actually suppress EOI
broadcasts when the suppression feature is enabled by the guest
(currently limited to split IRQCHIP, i.e. userspace I/O APIC).
Sadly, simply fixing KVM to honor Suppress EOI Broadcasts isn't an
option as some userspaces have come to rely on KVM's buggy behavior
(KVM advertises Supress EOI Broadcast irrespective of whether or
not userspace I/O APIC supports Directed EOIs)
- Clean up KVM's handling of marking mapped vCPU pages dirty
- Drop a pile of *ancient* sanity checks hidden behind in KVM's
unused ASSERT() macro, most of which could be trivially triggered
by the guest and/or user, and all of which were useless
- Fold "struct dest_map" into its sole user, "struct rtc_status", to
make it more obvious what the weird parameter is used for, and to
allow fropping these RTC shenanigans if CONFIG_KVM_IOAPIC=n
- Bury all of ioapic.h, i8254.h and related ioctls (including
KVM_CREATE_IRQCHIP) behind CONFIG_KVM_IOAPIC=y
- Add a regression test for recent APICv update fixes
- Handle "hardware APIC ISR", a.k.a. SVI, updates in
kvm_apic_update_apicv() to consolidate the updates, and to
co-locate SVI updates with the updates for KVM's own cache of ISR
information
- Drop a dead function declaration
- Minor cleanups
x86 (Intel):
- Rework KVM's handling of VMCS updates while L2 is active to
temporarily switch to vmcs01 instead of deferring the update until
the next nested VM-Exit.
The deferred updates approach directly contributed to several bugs,
was proving to be a maintenance burden due to the difficulty in
auditing the correctness of deferred updates, and was polluting
"struct nested_vmx" with a growing pile of booleans
- Fix an SGX bug where KVM would incorrectly try to handle EPCM page
faults, and instead always reflect them into the guest. Since KVM
doesn't shadow EPCM entries, EPCM violations cannot be due to KVM
interference and can't be resolved by KVM
- Fix a bug where KVM would register its posted interrupt wakeup
handler even if loading kvm-intel.ko ultimately failed
- Disallow access to vmcb12 fields that aren't fully supported,
mostly to avoid weirdness and complexity for FRED and other
features, where KVM wants enable VMCS shadowing for fields that
conditionally exist
- Print out the "bad" offsets and values if kvm-intel.ko refuses to
load (or refuses to online a CPU) due to a VMCS config mismatch
x86 (AMD):
- Drop a user-triggerable WARN on nested_svm_load_cr3() failure
- Add support for virtualizing ERAPS. Note, correct virtualization of
ERAPS relies on an upcoming, publicly announced change in the APM
to reduce the set of conditions where hardware (i.e. KVM) *must*
flush the RAP
- Ignore nSVM intercepts for instructions that are not supported
according to L1's virtual CPU model
- Add support for expedited writes to the fast MMIO bus, a la VMX's
fastpath for EPT Misconfig
- Don't set GIF when clearing EFER.SVME, as GIF exists independently
of SVM, and allow userspace to restore nested state with GIF=0
- Treat exit_code as an unsigned 64-bit value through all of KVM
- Add support for fetching SNP certificates from userspace
- Fix a bug where KVM would use vmcb02 instead of vmcb01 when
emulating VMLOAD or VMSAVE on behalf of L2
- Misc fixes and cleanups
x86 selftests:
- Add a regression test for TPR<=>CR8 synchronization and IRQ masking
- Overhaul selftest's MMU infrastructure to genericize stage-2 MMU
support, and extend x86's infrastructure to support EPT and NPT
(for L2 guests)
- Extend several nested VMX tests to also cover nested SVM
- Add a selftest for nested VMLOAD/VMSAVE
- Rework the nested dirty log test, originally added as a regression
test for PML where KVM logged L2 GPAs instead of L1 GPAs, to
improve test coverage and to hopefully make the test easier to
understand and maintain
guest_memfd:
- Remove kvm_gmem_populate()'s preparation tracking and half-baked
hugepage handling. SEV/SNP was the only user of the tracking and it
can do it via the RMP
- Retroactively document and enforce (for SNP) that
KVM_SEV_SNP_LAUNCH_UPDATE and KVM_TDX_INIT_MEM_REGION require the
source page to be 4KiB aligned, to avoid non-trivial complexity for
something that no known VMM seems to be doing and to avoid an API
special case for in-place conversion, which simply can't support
unaligned sources
- When populating guest_memfd memory, GUP the source page in common
code and pass the refcounted page to the vendor callback, instead
of letting vendor code do the heavy lifting. Doing so avoids a
looming deadlock bug with in-place due an AB-BA conflict betwee
mmap_lock and guest_memfd's filemap invalidate lock
Generic:
- Fix a bug where KVM would ignore the vCPU's selected address space
when creating a vCPU-specific mapping of guest memory. Actually
this bug could not be hit even on x86, the only architecture with
multiple address spaces, but it's a bug nevertheless"
* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm: (267 commits)
KVM: s390: Increase permitted SE header size to 1 MiB
MAINTAINERS: Replace backup for s390 vfio-pci
KVM: s390: vsie: Fix race in acquire_gmap_shadow()
KVM: s390: vsie: Fix race in walk_guest_tables()
KVM: s390: Use guest address to mark guest page dirty
irqchip/riscv-imsic: Adjust the number of available guest irq files
RISC-V: KVM: Transparent huge page support
RISC-V: KVM: selftests: Add Zalasr extensions to get-reg-list test
RISC-V: KVM: Allow Zalasr extensions for Guest/VM
KVM: riscv: selftests: Add riscv vm satp modes
KVM: riscv: selftests: add Zilsd and Zclsd extension to get-reg-list test
riscv: KVM: allow Zilsd and Zclsd extensions for Guest/VM
RISC-V: KVM: Skip IMSIC update if vCPU IMSIC state is not initialized
RISC-V: KVM: Fix null pointer dereference in kvm_riscv_aia_imsic_rw_attr()
RISC-V: KVM: Fix null pointer dereference in kvm_riscv_aia_imsic_has_attr()
RISC-V: KVM: Remove unnecessary 'ret' assignment
KVM: s390: Add explicit padding to struct kvm_s390_keyop
KVM: LoongArch: selftests: Add steal time test case
LoongArch: KVM: Add paravirt vcpu_is_preempted() support in guest side
LoongArch: KVM: Add paravirt preempt feature in hypervisor side
...
- gmap rewrite: completely new memory management for kvm/s390
- vSIE improvement
- maintainership change for s390 vfio-pci
- small quality of life improvement for protected guests
KVM guest_memfd changes for 6.20
- Remove kvm_gmem_populate()'s preparation tracking and half-baked hugepage
handling, and instead rely on SNP (the only user of the tracking) to do its
own tracking via the RMP.
- Retroactively document and enforce (for SNP) that KVM_SEV_SNP_LAUNCH_UPDATE
and KVM_TDX_INIT_MEM_REGION require the source page to be 4KiB aligned, to
avoid non-trivial complexity for a non-existent usecase (and because
in-place conversion simply can't support unaligned sources).
- When populating guest_memfd memory, GUP the source page in common code and
pass the refcounted page to the vendor callback, instead of letting vendor
code do the heavy lifting. Doing so avoids a looming deadlock bug with
in-place due an AB-BA conflict betwee mmap_lock and guest_memfd's filemap
invalidate lock.
Pull documentation updates from Jonathan Corbet:
"A slightly calmer cycle for docs this time around, though there is
still a fair amount going on, including:
- Some signs of life on the long-moribund Japanese translation
- Documentation on policies around the use of generative tools for
patch submissions, and a separate document intended for consumption
by generative tools
- The completion of the move of the documentation tools to
tools/docs. For now we're leaving a /scripts/kernel-doc symlink
behind to avoid breaking scripts
- Ongoing build-system work includes the incorporation of
documentation in Python code, better support for documenting
variables, and lots of improvements and fixes
- Automatic linking of man-page references -- cat(1), for example --
to the online pages in the HTML build
...and the usual array of typo fixes and such"
* tag 'docs-7.0' of git://git.kernel.org/pub/scm/linux/kernel/git/docs/linux: (107 commits)
doc: development-process: add notice on testing
tools: sphinx-build-wrapper: improve its help message
docs: sphinx-build-wrapper: allow -v override -q
docs: kdoc: Fix pdfdocs build for tools
docs: ja_JP: process: translate 'Obtain a current source tree'
docs: fix 're-use' -> 'reuse' in documentation
docs: ioctl-number: fix a typo in ioctl-number.rst
docs: filesystems: ensure proc pid substitutable is complete
docs: automarkup.py: Skip common English words as C identifiers
Documentation: use a source-read extension for the index link boilerplate
docs: parse_features: make documentation more consistent
docs: add parse_features module documentation
docs: jobserver: do some documentation improvements
docs: add jobserver module documentation
docs: kabi: helpers: add documentation for each "enum" value
docs: kabi: helpers: add helper for debug bits 7 and 8
docs: kabi: system_symbols: end docstring phrases with a dot
docs: python: abi_regex: do some improvements at documentation
docs: python: abi_parser: do some improvements at documentation
docs: add kabi modules documentation
...
KVM x86 misc changes for 6.20
- Disallow changing the virtual CPU model if L2 is active, for all the same
reasons KVM disallows change the model after the first KVM_RUN.
- Fix a bug where KVM would incorrectly reject host accesses to PV MSRs that
were advertised as supported to userspace when running with
KVM_CAP_ENFORCE_PV_FEATURE_CPUID enabled.
- Fix a bug where KVM would attempt to read protect guest state (CR3) when
configuring an async #PF entry.
- Fail the build if EXPORT_SYMBOL_GPL or EXPORT_SYMBOL is used in KVM (for x86
only) to enforce usage of EXPORT_SYMBOL_FOR_KVM_INTERNAL. Explicitly allow
the few exports that are intended for external usage.
- Ignore -EBUSY when checking nested events after a vCPU exits blocking as
the WARN is user-triggerable, and because exiting to userspace on -EBUSY
does more harm than good in pretty much every situation.
- Throw in the towel and drop the WARN on INIT/SIPI being blocked when vCPU is
in Wait-For-SIPI, as playing whack-a-mole with syzkaller turned out to be an
unwinnable game.
- Add support for new Intel instructions that don't require anything beyond
enumerating feature flags to userspace.
- Grab SRCU when reading PDPTRs in KVM_GET_SREGS2.
- Add WARNs to guard against modifying KVM's CPU caps outside of the intended
setup flow, as nested VMX in particular is sensitive to unexpected changes
in KVM's golden configuration.
- Add a quirk to allow userspace to opt-in to actually suppress EOI broadcasts
when the suppression feature is enabled by the guest (currently limited to
split IRQCHIP, i.e. userspace I/O APIC). Sadly, simply fixing KVM to honor
Suppress EOI Broadcasts isn't an option as some userspaces have come to rely
on KVM's buggy behavior (KVM advertises Supress EOI Broadcast irrespective
of whether or not userspace I/O APIC supports Directed EOIs).
- Minor cleanups.
KVM SVM changes for 6.20
- Drop a user-triggerable WARN on nested_svm_load_cr3() failure.
- Add support for virtualizing ERAPS. Note, correct virtualization of ERAPS
relies on an upcoming, publicly announced change in the APM to reduce the
set of conditions where hardware (i.e. KVM) *must* flush the RAP.
- Ignore nSVM intercepts for instructions that are not supported according to
L1's virtual CPU model.
- Add support for expedited writes to the fast MMIO bus, a la VMX's fastpath
for EPT Misconfig.
- Don't set GIF when clearing EFER.SVME, as GIF exists independently of SVM,
and allow userspace to restore nested state with GIF=0.
- Treat exit_code as an unsigned 64-bit value through all of KVM.
- Add support for fetching SNP certificates from userspace.
- Fix a bug where KVM would use vmcb02 instead of vmcb01 when emulating VMLOAD
or VMSAVE on behalf of L2.
- Misc fixes and cleanups.
Add a new IOCTL to allow userspace to manipulate storage keys directly.
This will make it easier to write selftests related to storage keys.
Acked-by: Heiko Carstens <hca@linux.ibm.com>
Signed-off-by: Claudio Imbrenda <imbrenda@linux.ibm.com>
Add two flags for KVM_CAP_X2APIC_API to allow userspace to control support
for Suppress EOI Broadcasts when using a split IRQCHIP (I/O APIC emulated
by userspace), which KVM completely mishandles. When x2APIC support was
first added, KVM incorrectly advertised and "enabled" Suppress EOI
Broadcast, without fully supporting the I/O APIC side of the equation,
i.e. without adding directed EOI to KVM's in-kernel I/O APIC.
That flaw was carried over to split IRQCHIP support, i.e. KVM advertised
support for Suppress EOI Broadcasts irrespective of whether or not the
userspace I/O APIC implementation supported directed EOIs. Even worse,
KVM didn't actually suppress EOI broadcasts, i.e. userspace VMMs without
support for directed EOI came to rely on the "spurious" broadcasts.
KVM "fixed" the in-kernel I/O APIC implementation by completely disabling
support for Suppress EOI Broadcasts in commit 0bcc3fb95b ("KVM: lapic:
stop advertising DIRECTED_EOI when in-kernel IOAPIC is in use"), but
didn't do anything to remedy userspace I/O APIC implementations.
KVM's bogus handling of Suppress EOI Broadcast is problematic when the
guest relies on interrupts being masked in the I/O APIC until well after
the initial local APIC EOI. E.g. Windows with Credential Guard enabled
handles interrupts in the following order:
1. Interrupt for L2 arrives.
2. L1 APIC EOIs the interrupt.
3. L1 resumes L2 and injects the interrupt.
4. L2 EOIs after servicing.
5. L1 performs the I/O APIC EOI.
Because KVM EOIs the I/O APIC at step #2, the guest can get an interrupt
storm, e.g. if the IRQ line is still asserted and userspace reacts to the
EOI by re-injecting the IRQ, because the guest doesn't de-assert the line
until step #4, and doesn't expect the interrupt to be re-enabled until
step #5.
Unfortunately, simply "fixing" the bug isn't an option, as KVM has no way
of knowing if the userspace I/O APIC supports directed EOIs, i.e.
suppressing EOI broadcasts would result in interrupts being stuck masked
in the userspace I/O APIC due to step #5 being ignored by userspace. And
fully disabling support for Suppress EOI Broadcast is also undesirable, as
picking up the fix would require a guest reboot, *and* more importantly
would change the virtual CPU model exposed to the guest without any buy-in
from userspace.
Add KVM_X2APIC_ENABLE_SUPPRESS_EOI_BROADCAST and
KVM_X2APIC_DISABLE_SUPPRESS_EOI_BROADCAST flags to allow userspace to
explicitly enable or disable support for Suppress EOI Broadcasts. This
gives userspace control over the virtual CPU model exposed to the guest,
as KVM should never have enabled support for Suppress EOI Broadcast without
userspace opt-in. Not setting either flag will result in legacy quirky
behavior for backward compatibility.
Disallow fully enabling SUPPRESS_EOI_BROADCAST when using an in-kernel
I/O APIC, as KVM's history/support is just as tragic. E.g. it's not clear
that commit c806a6ad35 ("KVM: x86: call irq notifiers with directed EOI")
was entirely correct, i.e. it may have simply papered over the lack of
Directed EOI emulation in the I/O APIC.
Note, Suppress EOI Broadcasts is defined only in Intel's SDM, not in AMD's
APM. But the bit is writable on some AMD CPUs, e.g. Turin, and KVM's ABI
is to support Directed EOI (KVM's name) irrespective of guest CPU vendor.
Fixes: 7543a635aa ("KVM: x86: Add KVM exit for IOAPIC EOIs")
Closes: https://lore.kernel.org/kvm/7D497EF1-607D-4D37-98E7-DAF95F099342@nutanix.com
Cc: stable@vger.kernel.org
Suggested-by: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: Khushit Shah <khushit.shah@nutanix.com>
Link: https://patch.msgid.link/20260123125657.3384063-1-khushit.shah@nutanix.com
[sean: clean up minor formatting goofs and fix a comment typo]
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
The root document usually has a special :ref:`genindex` link to the
generated index. This is also the case for Documentation/index.rst. The
other index.rst files deeper in the directory hierarchy usually don't.
For SPHINXDIRS builds, the root document isn't Documentation/index.rst,
but some other index.rst in the hierarchy. Currently they have a
".. only::" block to add the index link when doing SPHINXDIRS html
builds.
This is obviously very tedious and repetitive. The link is also added to
all index.rst files in the hierarchy for SPHINXDIRS builds, not just the
root document.
Put the boilerplate in a sphinx-includes/subproject-index.rst file, and
include it at the end of the root document for subproject builds in an
ad-hoc source-read extension defined in conf.py.
For now, keep having the boilerplate in translations, because this
approach currently doesn't cover translated index link headers.
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mauro Carvalho Chehab <mchehab@kernel.org>
Cc: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Tested-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
Reviewed-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>
[jc: did s/doctree/kern_doc_dir/ ]
Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Message-ID: <20260123143149.2024303-1-jani.nikula@intel.com>
For SEV-SNP, the host can optionally provide a certificate table to the
guest when it issues an attestation request to firmware (see GHCB 2.0
specification regarding "SNP Extended Guest Requests"). This certificate
table can then be used to verify the endorsement key used by firmware to
sign the attestation report.
While it is possible for guests to obtain the certificates through other
means, handling it via the host provides more flexibility in being able
to keep the certificate data in sync with the endorsement key throughout
host-side operations that might resulting in the endorsement key
changing.
In the case of KVM, userspace will be responsible for fetching the
certificate table and keeping it in sync with any modifications to the
endorsement key by other userspace management tools. Define a new
KVM_EXIT_SNP_REQ_CERTS event where userspace is provided with the GPA of
the buffer the guest has provided as part of the attestation request so
that userspace can write the certificate data into it while relying on
filesystem-based locking to keep the certificates up-to-date relative to
the endorsement keys installed/utilized by firmware at the time the
certificates are fetched.
[Melody: Update the documentation scheme about how file locking is
expected to happen.]
Reviewed-by: Liam Merwick <liam.merwick@oracle.com>
Tested-by: Liam Merwick <liam.merwick@oracle.com>
Tested-by: Dionna Glaze <dionnaglaze@google.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Signed-off-by: Melody Wang <huibo.wang@amd.com>
Signed-off-by: Michael Roth <michael.roth@amd.com>
Link: https://patch.msgid.link/20260109231732.1160759-2-michael.roth@amd.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
