When using the "install" or targets depending on install, e.g. "gen_tar",
the BPF machine flavors weren't included.
A command like:
| make ARCH=riscv CROSS_COMPILE=riscv64-linux-gnu- O=/workspace/kbuild \
| HOSTCC=gcc FORMAT= SKIP_TARGETS="arm64 ia64 powerpc sparc64 x86 sgx" \
| -C tools/testing/selftests gen_tar
would not include bpf/no_alu32, bpf/cpuv4, or bpf/bpf-gcc.
Include the BPF machine flavors for "install" make target.
Signed-off-by: Björn Töpel <bjorn@rivosinc.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20230831162954.111485-1-bjorn@kernel.org
syzbot reported a data race splat between two processes trying to
update the same BPF map value via syscall on different CPUs:
BUG: KCSAN: data-race in bpf_percpu_array_update / bpf_percpu_array_update
write to 0xffffe8fffe7425d8 of 8 bytes by task 8257 on cpu 1:
bpf_long_memcpy include/linux/bpf.h:428 [inline]
bpf_obj_memcpy include/linux/bpf.h:441 [inline]
copy_map_value_long include/linux/bpf.h:464 [inline]
bpf_percpu_array_update+0x3bb/0x500 kernel/bpf/arraymap.c:380
bpf_map_update_value+0x190/0x370 kernel/bpf/syscall.c:175
generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1749
bpf_map_do_batch+0x2df/0x3d0 kernel/bpf/syscall.c:4648
__sys_bpf+0x28a/0x780
__do_sys_bpf kernel/bpf/syscall.c:5241 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5239 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5239
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
write to 0xffffe8fffe7425d8 of 8 bytes by task 8268 on cpu 0:
bpf_long_memcpy include/linux/bpf.h:428 [inline]
bpf_obj_memcpy include/linux/bpf.h:441 [inline]
copy_map_value_long include/linux/bpf.h:464 [inline]
bpf_percpu_array_update+0x3bb/0x500 kernel/bpf/arraymap.c:380
bpf_map_update_value+0x190/0x370 kernel/bpf/syscall.c:175
generic_map_update_batch+0x3ae/0x4f0 kernel/bpf/syscall.c:1749
bpf_map_do_batch+0x2df/0x3d0 kernel/bpf/syscall.c:4648
__sys_bpf+0x28a/0x780
__do_sys_bpf kernel/bpf/syscall.c:5241 [inline]
__se_sys_bpf kernel/bpf/syscall.c:5239 [inline]
__x64_sys_bpf+0x43/0x50 kernel/bpf/syscall.c:5239
do_syscall_x64 arch/x86/entry/common.c:50 [inline]
do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
entry_SYSCALL_64_after_hwframe+0x63/0xcd
value changed: 0x0000000000000000 -> 0xfffffff000002788
The bpf_long_memcpy is used with 8-byte aligned pointers, power-of-8 size
and forced to use long read/writes to try to atomically copy long counters.
It is best-effort only and no barriers are here since it _will_ race with
concurrent updates from BPF programs. The bpf_long_memcpy() is called from
bpf(2) syscall. Marco suggested that the best way to make this known to
KCSAN would be to use data_race() annotation.
Reported-by: syzbot+97522333291430dd277f@syzkaller.appspotmail.com
Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Marco Elver <elver@google.com>
Link: https://lore.kernel.org/bpf/000000000000d87a7f06040c970c@google.com
Link: https://lore.kernel.org/bpf/57628f7a15e20d502247c3b55fceb1cb2b31f266.1693342186.git.daniel@iogearbox.net
Pull ARM updates from Russell King:
- Refactor VFP code and convert to C code (Ard Biesheuvel)
- Fix hardware breakpoint single-stepping using bpf_overflow_handler
- Make SMP stop calls asynchronous allowing panic from irq context to
work
- Fix for kernel-doc warnings for locomo
* tag 'for-linus' of git://git.armlinux.org.uk/~rmk/linux-arm:
Revert part of ae1f8d793a ("ARM: 9304/1: add prototype for function called only from asm")
ARM: 9318/1: locomo: move kernel-doc to prevent warnings
ARM: 9317/1: kexec: Make smp stop calls asynchronous
ARM: 9316/1: hw_breakpoint: fix single-stepping when using bpf_overflow_handler
ARM: entry: Make asm coproc dispatch code NWFPE only
ARM: iwmmxt: Use undef hook to enable coprocessor for task
ARM: entry: Disregard Thumb undef exception in coproc dispatch
ARM: vfp: Use undef hook for handling VFP exceptions
ARM: kernel: Get rid of thread_info::used_cp[] array
ARM: vfp: Reimplement VFP exception entry in C code
ARM: vfp: Remove workaround for Feroceon CPUs
ARM: vfp: Record VFP bounces as perf emulation faults
Pull powerpc updates from Michael Ellerman:
- Add HOTPLUG_SMT support (/sys/devices/system/cpu/smt) and honour the
configured SMT state when hotplugging CPUs into the system
- Combine final TLB flush and lazy TLB mm shootdown IPIs when using the
Radix MMU to avoid a broadcast TLBIE flush on exit
- Drop the exclusion between ptrace/perf watchpoints, and drop the now
unused associated arch hooks
- Add support for the "nohlt" command line option to disable CPU idle
- Add support for -fpatchable-function-entry for ftrace, with GCC >=
13.1
- Rework memory block size determination, and support 256MB size on
systems with GPUs that have hotpluggable memory
- Various other small features and fixes
Thanks to Andrew Donnellan, Aneesh Kumar K.V, Arnd Bergmann, Athira
Rajeev, Benjamin Gray, Christophe Leroy, Frederic Barrat, Gautam
Menghani, Geoff Levand, Hari Bathini, Immad Mir, Jialin Zhang, Joel
Stanley, Jordan Niethe, Justin Stitt, Kajol Jain, Kees Cook, Krzysztof
Kozlowski, Laurent Dufour, Liang He, Linus Walleij, Mahesh Salgaonkar,
Masahiro Yamada, Michal Suchanek, Nageswara R Sastry, Nathan Chancellor,
Nathan Lynch, Naveen N Rao, Nicholas Piggin, Nick Desaulniers, Omar
Sandoval, Randy Dunlap, Reza Arbab, Rob Herring, Russell Currey, Sourabh
Jain, Thomas Gleixner, Trevor Woerner, Uwe Kleine-König, Vaibhav Jain,
Xiongfeng Wang, Yuan Tan, Zhang Rui, and Zheng Zengkai.
* tag 'powerpc-6.6-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (135 commits)
macintosh/ams: linux/platform_device.h is needed
powerpc/xmon: Reapply "Relax frame size for clang"
powerpc/mm/book3s64: Use 256M as the upper limit with coherent device memory attached
powerpc/mm/book3s64: Fix build error with SPARSEMEM disabled
powerpc/iommu: Fix notifiers being shared by PCI and VIO buses
powerpc/mpc5xxx: Add missing fwnode_handle_put()
powerpc/config: Disable SLAB_DEBUG_ON in skiroot
powerpc/pseries: Remove unused hcall tracing instruction
powerpc/pseries: Fix hcall tracepoints with JUMP_LABEL=n
powerpc: dts: add missing space before {
powerpc/eeh: Use pci_dev_id() to simplify the code
powerpc/64s: Move CPU -mtune options into Kconfig
powerpc/powermac: Fix unused function warning
powerpc/pseries: Rework lppaca_shared_proc() to avoid DEBUG_PREEMPT
powerpc: Don't include lppaca.h in paca.h
powerpc/pseries: Move hcall_vphn() prototype into vphn.h
powerpc/pseries: Move VPHN constants into vphn.h
cxl: Drop unused detach_spa()
powerpc: Drop zalloc_maybe_bootmem()
powerpc/powernv: Use struct opal_prd_msg in more places
...
Fix this makecheck warning:
drivers/parisc/sba_iommu.c:98:19: warning: symbol 'sba_list'
was not declared. Should it be static?
Signed-off-by: Helge Deller <deller@gmx.de>
The no_value field in 'struct parse_events_term' indicates that the val
variable isn't used, the case for an event name.
Cloning wasn't propagating this, making cloned event name terms
appearing to have a constant assinged to them.
Working around the bug would check for a value of 1 assigned to value,
but then this meant a user value of 1 couldn't be differentiated causing
the value to be lost in debug printing and perf list.
The change fixes the cloning and updates the "val.num ==/!= 1" tests to
use no_value instead.
To better check the no_value is set appropriately parameter comments are
added for constant values.
This found that no_value wasn't set correctly in parse_events_multi_pmu_add,
which matters now that no_value is used to indicate an event name.
Fixes: 7a6e916447 ("perf parse-events: Make common term list to strbuf helper")
Fixes: 99e7138eb7 ("perf tools: Fail on using multiple bits long terms without value")
Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Kan Liang <kan.liang@linux.intel.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rob Herring <robh@kernel.org>
Link: https://lore.kernel.org/r/20230831071421.2201358-4-irogers@google.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Pull x86 shadow stack support from Dave Hansen:
"This is the long awaited x86 shadow stack support, part of Intel's
Control-flow Enforcement Technology (CET).
CET consists of two related security features: shadow stacks and
indirect branch tracking. This series implements just the shadow stack
part of this feature, and just for userspace.
The main use case for shadow stack is providing protection against
return oriented programming attacks. It works by maintaining a
secondary (shadow) stack using a special memory type that has
protections against modification. When executing a CALL instruction,
the processor pushes the return address to both the normal stack and
to the special permission shadow stack. Upon RET, the processor pops
the shadow stack copy and compares it to the normal stack copy.
For more information, refer to the links below for the earlier
versions of this patch set"
Link: https://lore.kernel.org/lkml/20220130211838.8382-1-rick.p.edgecombe@intel.com/
Link: https://lore.kernel.org/lkml/20230613001108.3040476-1-rick.p.edgecombe@intel.com/
* tag 'x86_shstk_for_6.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (47 commits)
x86/shstk: Change order of __user in type
x86/ibt: Convert IBT selftest to asm
x86/shstk: Don't retry vm_munmap() on -EINTR
x86/kbuild: Fix Documentation/ reference
x86/shstk: Move arch detail comment out of core mm
x86/shstk: Add ARCH_SHSTK_STATUS
x86/shstk: Add ARCH_SHSTK_UNLOCK
x86: Add PTRACE interface for shadow stack
selftests/x86: Add shadow stack test
x86/cpufeatures: Enable CET CR4 bit for shadow stack
x86/shstk: Wire in shadow stack interface
x86: Expose thread features in /proc/$PID/status
x86/shstk: Support WRSS for userspace
x86/shstk: Introduce map_shadow_stack syscall
x86/shstk: Check that signal frame is shadow stack mem
x86/shstk: Check that SSP is aligned on sigreturn
x86/shstk: Handle signals for shadow stack
x86/shstk: Introduce routines modifying shstk
x86/shstk: Handle thread shadow stack
x86/shstk: Add user-mode shadow stack support
...
The Gather Data Sampling (GDS) vulnerability is common to all Skylake
processors. However, the "client" Skylakes* are now in this list:
https://www.intel.com/content/www/us/en/support/articles/000022396/processors.html
which means they are no longer included for new vulnerabilities here:
https://www.intel.com/content/www/us/en/developer/topic-technology/software-security-guidance/processors-affected-consolidated-product-cpu-model.html
or in other GDS documentation. Thus, they were not included in the
original GDS mitigation patches.
Mark SKYLAKE and SKYLAKE_L as vulnerable to GDS to match all the
other Skylake CPUs (which include Kaby Lake). Also group the CPUs
so that the ones that share the exact same vulnerabilities are next
to each other.
Last, move SRBDS to the end of each line. This makes it clear at a
glance that SKYLAKE_X is unique. Of the five Skylakes, it is the
only "server" CPU and has a different implementation from the
clients of the "special register" hardware, making it immune to SRBDS.
This makes the diff much harder to read, but the resulting table is
worth it.
I very much appreciate the report from Michael Zhivich about this
issue. Despite what level of support a hardware vendor is providing,
the kernel very much needs an accurate and up-to-date list of
vulnerable CPUs. More reports like this are very welcome.
* Client Skylakes are CPUID 406E3/506E3 which is family 6, models
0x4E and 0x5E, aka INTEL_FAM6_SKYLAKE and INTEL_FAM6_SKYLAKE_L.
Reported-by: Michael Zhivich <mzhivich@akamai.com>
Fixes: 8974eb5882 ("x86/speculation: Add Gather Data Sampling mitigation")
Signed-off-by: Dave Hansen <dave.hansen@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Daniel Sneddon <daniel.sneddon@linux.intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Explicitly include mmu.h in spte.h instead of relying on the "parent" to
include mmu.h. spte.h references a variety of macros and variables that
are defined/declared in mmu.h, and so including spte.h before (or instead
of) mmu.h will result in build errors, e.g.
arch/x86/kvm/mmu/spte.h: In function ‘is_mmio_spte’:
arch/x86/kvm/mmu/spte.h:242:23: error: ‘enable_mmio_caching’ undeclared
242 | likely(enable_mmio_caching);
| ^~~~~~~~~~~~~~~~~~~
arch/x86/kvm/mmu/spte.h: In function ‘is_large_pte’:
arch/x86/kvm/mmu/spte.h:302:22: error: ‘PT_PAGE_SIZE_MASK’ undeclared
302 | return pte & PT_PAGE_SIZE_MASK;
| ^~~~~~~~~~~~~~~~~
arch/x86/kvm/mmu/spte.h: In function ‘is_dirty_spte’:
arch/x86/kvm/mmu/spte.h:332:56: error: ‘PT_WRITABLE_MASK’ undeclared
332 | return dirty_mask ? spte & dirty_mask : spte & PT_WRITABLE_MASK;
| ^~~~~~~~~~~~~~~~
Fixes: 5a9624affe ("KVM: mmu: extract spte.h and spte.c")
Link: https://lore.kernel.org/r/20230808224059.2492476-1-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When attempting to allocate a shadow root for a !visible guest root gfn,
e.g. that resides in MMIO space, load a dummy root that is backed by the
zero page instead of immediately synthesizing a triple fault shutdown
(using the zero page ensures any attempt to translate memory will generate
a !PRESENT fault and thus VM-Exit).
Unless the vCPU is racing with memslot activity, KVM will inject a page
fault due to not finding a visible slot in FNAME(walk_addr_generic), i.e.
the end result is mostly same, but critically KVM will inject a fault only
*after* KVM runs the vCPU with the bogus root.
Waiting to inject a fault until after running the vCPU fixes a bug where
KVM would bail from nested VM-Enter if L1 tried to run L2 with TDP enabled
and a !visible root. Even though a bad root will *probably* lead to
shutdown, (a) it's not guaranteed and (b) the CPU won't read the
underlying memory until after VM-Enter succeeds. E.g. if L1 runs L2 with
a VMX preemption timer value of '0', then architecturally the preemption
timer VM-Exit is guaranteed to occur before the CPU executes any
instruction, i.e. before the CPU needs to translate a GPA to a HPA (so
long as there are no injected events with higher priority than the
preemption timer).
If KVM manages to get to FNAME(fetch) with a dummy root, e.g. because
userspace created a memslot between installing the dummy root and handling
the page fault, simply unload the MMU to allocate a new root and retry the
instruction. Use KVM_REQ_MMU_FREE_OBSOLETE_ROOTS to drop the root, as
invoking kvm_mmu_free_roots() while holding mmu_lock would deadlock, and
conceptually the dummy root has indeeed become obsolete. The only
difference versus existing usage of KVM_REQ_MMU_FREE_OBSOLETE_ROOTS is
that the root has become obsolete due to memslot *creation*, not memslot
deletion or movement.
Reported-by: Reima Ishii <ishiir@g.ecc.u-tokyo.ac.jp>
Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Link: https://lore.kernel.org/r/20230729005200.1057358-6-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Explicitly inject a page fault if guest attempts to use a !visible gfn
as a page table. kvm_vcpu_gfn_to_hva_prot() will naturally handle the
case where there is no memslot, but doesn't catch the scenario where the
gfn points at a KVM-internal memslot.
Letting the guest backdoor its way into accessing KVM-internal memslots
isn't dangerous on its own, e.g. at worst the guest can crash itself, but
disallowing the behavior will simplify fixing how KVM handles !visible
guest root gfns (immediately synthesizing a triple fault when loading the
root is architecturally wrong).
Link: https://lore.kernel.org/r/20230729005200.1057358-5-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Explicitly check that tdp_iter_start() is handed a valid shadow page
to harden KVM against bugs, e.g. if KVM calls into the TDP MMU with an
invalid or shadow MMU root (which would be a fatal KVM bug), the shadow
page pointer will be NULL.
Opportunistically stop the TDP MMU iteration instead of continuing on
with garbage if the incoming root is bogus. Attempting to walk a garbage
root is more likely to caused major problems than doing nothing.
Cc: Yu Zhang <yu.c.zhang@linux.intel.com>
Link: https://lore.kernel.org/r/20230729005200.1057358-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Harden kvm_mmu_new_pgd() against NULL pointer dereference bugs by sanity
checking that the target root has an associated shadow page prior to
dereferencing said shadow page. The code in question is guaranteed to
only see roots with shadow pages as fast_pgd_switch() explicitly frees the
current root if it doesn't have a shadow page, i.e. is a PAE root, and
that in turn prevents valid roots from being cached, but that's all very
subtle.
Link: https://lore.kernel.org/r/20230729005200.1057358-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a dedicated helper for converting a root hpa to a shadow page in
anticipation of using a "dummy" root to handle the scenario where KVM
needs to load a valid shadow root (from hardware's perspective), but
the guest doesn't have a visible root to shadow. Similar to PAE roots,
the dummy root won't have an associated kvm_mmu_page and will need special
handling when finding a shadow page given a root.
Opportunistically retrieve the root shadow page in kvm_mmu_sync_roots()
*after* verifying the root is unsync (the dummy root can never be unsync).
Link: https://lore.kernel.org/r/20230729005200.1057358-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Open code gpa_to_gfn() in kvmgt_page_track_write() and drop KVMGT's
dependency on kvm_host.h, i.e. include only kvm_page_track.h. KVMGT
assumes "gfn == gpa >> PAGE_SHIFT" all over the place, including a few
lines below in the same function with the same gpa, i.e. there's no
reason to use KVM's helper for this one case.
No functional change intended.
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-30-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Rename the page-track APIs to capture that they're all about tracking
writes, now that the facade of supporting multiple modes is gone.
Opportunstically replace "slot" with "gfn" in anticipation of removing
the @slot param from the external APIs.
No functional change intended.
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-25-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Drop "support" for multiple page-track modes, as there is no evidence
that array-based and refcounted metadata is the optimal solution for
other modes, nor is there any evidence that other use cases, e.g. for
access-tracking, will be a good fit for the page-track machinery in
general.
E.g. one potential use case of access-tracking would be to prevent guest
access to poisoned memory (from the guest's perspective). In that case,
the number of poisoned pages is likely to be a very small percentage of
the guest memory, and there is no need to reference count the number of
access-tracking users, i.e. expanding gfn_track[] for a new mode would be
grossly inefficient. And for poisoned memory, host userspace would also
likely want to trap accesses, e.g. to inject #MC into the guest, and that
isn't currently supported by the page-track framework.
A better alternative for that poisoned page use case is likely a
variation of the proposed per-gfn attributes overlay (linked), which
would allow efficiently tracking the sparse set of poisoned pages, and by
default would exit to userspace on access.
Link: https://lore.kernel.org/all/Y2WB48kD0J4VGynX@google.com
Cc: Ben Gardon <bgardon@google.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-24-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Disable the page-track notifier code at compile time if there are no
external users, i.e. if CONFIG_KVM_EXTERNAL_WRITE_TRACKING=n. KVM itself
now hooks emulated writes directly instead of relying on the page-track
mechanism.
Provide a stub for "struct kvm_page_track_notifier_node" so that including
headers directly from the command line, e.g. for testing include guards,
doesn't fail due to a struct having an incomplete type.
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-23-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bury the declaration of the page-track helpers that are intended only for
internal KVM use in a "private" header. In addition to guarding against
unwanted usage of the internal-only helpers, dropping their definitions
avoids exposing other structures that should be KVM-internal, e.g. for
memslots. This is a baby step toward making kvm_host.h a KVM-internal
header in the very distant future.
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-22-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a new page-track hook, track_remove_region(), that is called when a
memslot DELETE operation is about to be committed. The "remove" hook
will be used by KVMGT and will effectively replace the existing
track_flush_slot() altogether now that KVM itself doesn't rely on the
"flush" hook either.
The "flush" hook is flawed as it's invoked before the memslot operation
is guaranteed to succeed, i.e. KVM might ultimately keep the existing
memslot without notifying external page track users, a.k.a. KVMGT. In
practice, this can't currently happen on x86, but there are no guarantees
that won't change in the future, not to mention that "flush" does a very
poor job of describing what is happening.
Pass in the gfn+nr_pages instead of the slot itself so external users,
i.e. KVMGT, don't need to exposed to KVM internals (memslots). This will
help set the stage for additional cleanups to the page-track APIs.
Opportunistically align the existing srcu_read_lock_held() usage so that
the new case doesn't stand out like a sore thumb (and not aligning the
new code makes bots unhappy).
Cc: Zhenyu Wang <zhenyuw@linux.intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Signed-off-by: Yan Zhao <yan.y.zhao@intel.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-19-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Disallow moving memslots if the VM has external page-track users, i.e. if
KVMGT is being used to expose a virtual GPU to the guest, as KVMGT doesn't
correctly handle moving memory regions.
Note, this is potential ABI breakage! E.g. userspace could move regions
that aren't shadowed by KVMGT without harming the guest. However, the
only known user of KVMGT is QEMU, and QEMU doesn't move generic memory
regions. KVM's own support for moving memory regions was also broken for
multiple years (albeit for an edge case, but arguably moving RAM is
itself an edge case), e.g. see commit edd4fa37ba ("KVM: x86: Allocate
new rmap and large page tracking when moving memslot").
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-17-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Don't use the generic page-track mechanism to handle writes to guest PTEs
in KVM's MMU. KVM's MMU needs access to information that should not be
exposed to external page-track users, e.g. KVM needs (for some definitions
of "need") the vCPU to query the current paging mode, whereas external
users, i.e. KVMGT, have no ties to the current vCPU and so should never
need the vCPU.
Moving away from the page-track mechanism will allow dropping use of the
page-track mechanism for KVM's own MMU, and will also allow simplifying
and cleaning up the page-track APIs.
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-15-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move x86's implementation of kvm_arch_flush_shadow_{all,memslot}() into
mmu.c, and make kvm_mmu_zap_all() static as it was globally visible only
for kvm_arch_flush_shadow_all(). This will allow refactoring
kvm_arch_flush_shadow_memslot() to call kvm_mmu_zap_all() directly without
having to expose kvm_mmu_zap_all_fast() outside of mmu.c. Keeping
everything in mmu.c will also likely simplify supporting TDX, which
intends to do zap only relevant SPTEs on memslot updates.
No functional change intended.
Suggested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-13-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Use vgpu_lock instead of KVM's mmu_lock to protect accesses to the hash
table used to track which gfns are write-protected when shadowing the
guest's GTT, and hoist the acquisition of vgpu_lock from
intel_vgpu_page_track_handler() out to its sole caller,
kvmgt_page_track_write().
This fixes a bug where kvmgt_page_track_write(), which doesn't hold
kvm->mmu_lock, could race with intel_gvt_page_track_remove() and trigger
a use-after-free.
Fixing kvmgt_page_track_write() by taking kvm->mmu_lock is not an option
as mmu_lock is a r/w spinlock, and intel_vgpu_page_track_handler() might
sleep when acquiring vgpu->cache_lock deep down the callstack:
intel_vgpu_page_track_handler()
|
|-> page_track->handler / ppgtt_write_protection_handler()
|
|-> ppgtt_handle_guest_write_page_table_bytes()
|
|-> ppgtt_handle_guest_write_page_table()
|
|-> ppgtt_handle_guest_entry_removal()
|
|-> ppgtt_invalidate_pte()
|
|-> intel_gvt_dma_unmap_guest_page()
|
|-> mutex_lock(&vgpu->cache_lock);
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-12-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Drop intel_vgpu_reset_gtt() as it no longer has any callers. In addition
to eliminating dead code, this eliminates the last possible scenario where
__kvmgt_protect_table_find() can be reached without holding vgpu_lock.
Requiring vgpu_lock to be held when calling __kvmgt_protect_table_find()
will allow a protecting the gfn hash with vgpu_lock without too much fuss.
No functional change intended.
Fixes: ba25d97757 ("drm/i915/gvt: Do not destroy ppgtt_mm during vGPU D3->D0.")
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-11-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Now that gvt_pin_guest_page() explicitly verifies the pinned PFN is a
transparent hugepage page, don't use KVM's gfn_to_pfn() to pre-check if a
2MiB GTT entry is possible and instead just try to map the GFN with a 2MiB
entry. Using KVM to query pfn that is ultimately managed through VFIO is
odd, and KVM's gfn_to_pfn() is not intended for non-KVM consumption; it's
exported only because of KVM vendor modules (x86 and PPC).
Open code the check on 2MiB support instead of keeping
is_2MB_gtt_possible() around for a single line of code.
Move the call to intel_gvt_dma_map_guest_page() for a 4KiB entry into its
case statement, i.e. fork the common path into the 4KiB and 2MiB "direct"
shadow paths. Keeping the call in the "common" path is arguably more in
the spirit of "one change per patch", but retaining the local "page_size"
variable is silly, i.e. the call site will be changed either way, and
jumping around the no-longer-common code is more subtle and rather odd,
i.e. would just need to be immediately cleaned up.
Drop the error message from gvt_pin_guest_page() when KVMGT attempts to
shadow a 2MiB guest page that isn't backed by a compatible hugepage in the
host. Dropping the pre-check on a THP makes it much more likely that the
"error" will be encountered in normal operation.
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-9-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Bail from ppgtt_populate_shadow_entry() if an unexpected GTT entry type
is encountered instead of subtly falling through to the common "direct
shadow" path. Eliminating the default/error path's reliance on the common
handling will allow hoisting intel_gvt_dma_map_guest_page() into the case
statements so that the 2MiB case can try intel_gvt_dma_map_guest_page()
and fallback to splitting the entry on failure.
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-8-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Move the check that a vGPU is attached from is_2MB_gtt_possible() all the
way up to shadow_ppgtt_mm() to avoid unnecessary work, and to make it more
obvious that a future cleanup of is_2MB_gtt_possible() isn't introducing a
bug.
is_2MB_gtt_possible() has only one caller, ppgtt_populate_shadow_entry(),
and all paths in ppgtt_populate_shadow_entry() eventually check for
attachment by way of intel_gvt_dma_map_guest_page().
And of the paths that lead to ppgtt_populate_shadow_entry(),
shadow_ppgtt_mm() is the only one that doesn't already check for
INTEL_VGPU_STATUS_ACTIVE or INTEL_VGPU_STATUS_ATTACHED.
workload_thread() <= pick_next_workload() => INTEL_VGPU_STATUS_ACTIVE
|
-> dispatch_workload()
|
|-> prepare_workload()
|
-> intel_vgpu_sync_oos_pages()
| |
| |-> ppgtt_set_guest_page_sync()
| |
| |-> sync_oos_page()
| |
| |-> ppgtt_populate_shadow_entry()
|
|-> intel_vgpu_flush_post_shadow()
|
1: |-> ppgtt_handle_guest_write_page_table()
|
|-> ppgtt_handle_guest_entry_add()
|
2: | -> ppgtt_populate_spt_by_guest_entry()
| |
| |-> ppgtt_populate_spt()
| |
| |-> ppgtt_populate_shadow_entry()
| |
| |-> ppgtt_populate_spt_by_guest_entry() [see 2]
|
|-> ppgtt_populate_shadow_entry()
kvmgt_page_track_write() <= KVM callback => INTEL_VGPU_STATUS_ATTACHED
|
|-> intel_vgpu_page_track_handler()
|
|-> ppgtt_write_protection_handler()
|
|-> ppgtt_handle_guest_write_page_table_bytes()
|
|-> ppgtt_handle_guest_write_page_table() [see 1]
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Tested-by: Yan Zhao <yan.y.zhao@intel.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
When shadowing a GTT entry with a 2M page, verify that the pfns are
contiguous, not just that the struct page pointers are contiguous. The
memory map is virtual contiguous if "CONFIG_FLATMEM=y ||
CONFIG_SPARSEMEM_VMEMMAP=y", but not for "CONFIG_SPARSEMEM=y &&
CONFIG_SPARSEMEM_VMEMMAP=n", so theoretically KVMGT could encounter struct
pages that are virtually contiguous, but not physically contiguous.
In practice, this flaw is likely a non-issue as it would cause functional
problems iff a section isn't 2M aligned _and_ is directly adjacent to
another section with discontiguous pfns.
Tested-by: Yongwei Ma <yongwei.ma@intel.com>
Reviewed-by: Zhi Wang <zhi.a.wang@intel.com>
Reviewed-by: Yan Zhao <yan.y.zhao@intel.com>
Link: https://lore.kernel.org/r/20230729013535.1070024-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
