Commit 300bb1fe76 ("ptp: arm/arm64: Enable ptp_kvm for arm/arm64")
enable ptp_kvm support for ARM platforms and for any ARM platform that
does not support this, the following error message is displayed ...
ERR KERN fail to initialize ptp_kvm
For platforms that do not support ptp_kvm this error is a bit misleading
and so fix this by only printing this message if the error returned by
kvm_arch_ptp_init() is not -EOPNOTSUPP. Note that -EOPNOTSUPP is only
returned by ARM platforms today if ptp_kvm is not supported.
Fixes: 300bb1fe76 ("ptp: arm/arm64: Enable ptp_kvm for arm/arm64")
Signed-off-by: Jon Hunter <jonathanh@nvidia.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210420132419.1318148-1-jonathanh@nvidia.com
Provide the missing dummy bug_get_file_line() implementation when
GENENERIC_BUG isn't selected.
Reported-by: kernel test robot <lkp@intel.com>
Fixes: 26dbc7e299 ("bug: Factor out a getter for a bug's file line")
Cc: Andrew Scull <ascull@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
The sparse tool complains as follows:
drivers/hwtracing/coresight/coresight-core.c:26:1: warning:
symbol '__pcpu_scope_csdev_sink' was not declared. Should it be static?
As csdev_sink is not used outside of coresight-core.c after the
introduction of coresight_[set|get]_percpu_sink() helpers, this
change marks it static.
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Link: https://lore.kernel.org/r/20210409094900.1902783-1-weiyongjun1@huawei.com
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
When reading the base address of the a REDIST region
through KVM_VGIC_V3_ADDR_TYPE_REDIST we expect the
redistributor region list to be populated with a single
element.
However list_first_entry() expects the list to be non empty.
Instead we should use list_first_entry_or_null which effectively
returns NULL if the list is empty.
Fixes: dbd9733ab6 ("KVM: arm/arm64: Replace the single rdist region by a list")
Cc: <Stable@vger.kernel.org> # v4.18+
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Reported-by: Gavin Shan <gshan@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210412150034.29185-1-eric.auger@redhat.com
Kernel mode NEON can be used in task or softirq context, but only in
a non-nesting manner, i.e., softirq context is only permitted if the
interrupt was not taken at a point where the kernel was using the NEON
in task context.
This means all users of kernel mode NEON have to be aware of this
limitation, and either need to provide scalar fallbacks that may be much
slower (up to 20x for AES instructions) and potentially less safe, or
use an asynchronous interface that defers processing to a later time
when the NEON is guaranteed to be available.
Given that grabbing and releasing the NEON is cheap, we can relax this
restriction, by increasing the granularity of kernel mode NEON code, and
always disabling softirq processing while the NEON is being used in task
context.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210302090118.30666-4-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The AArch64 asm syntax has this slightly tedious property that the names
used in mnemonics to refer to registers depend on whether the opcode in
question targets the entire 64-bits (xN), or only the least significant
8, 16 or 32 bits (wN). When writing parameterized code such as macros,
this can be annoying, as macro arguments don't lend themselves to
indexed lookups, and so generating a reference to wN in a macro that
receives xN as an argument is problematic.
For instance, an upcoming patch that modifies the implementation of the
cond_yield macro to be able to refer to 32-bit registers would need to
modify invocations such as
cond_yield 3f, x8
to
cond_yield 3f, 8
so that the second argument can be token pasted after x or w to emit the
correct register reference. Unfortunately, this interferes with the self
documenting nature of the first example, where the second argument is
obviously a register, whereas in the second example, one would need to
go and look at the code to find out what '8' means.
So let's fix this by defining wxN aliases for all xN registers, which
resolve to the 32-bit alias of each respective 64-bit register. This
allows the macro implementation to paste the xN reference after a w to
obtain the correct register name.
Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210302090118.30666-3-ardb@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Even though KVM sets up MDCR_EL2 to trap accesses to the SPE buffer and
sampling control registers and to inject an undefined exception, the
presence of FEAT_SPE is still advertised in the ID_AA64DFR0_EL1 register,
if the hardware supports it. Getting an undefined exception when accessing
a register usually happens for a hardware feature which is not implemented,
and indeed this is how PMU emulation is handled when the virtual machine
has been created without the KVM_ARM_VCPU_PMU_V3 feature. Let's be
consistent and never advertise FEAT_SPE, because KVM doesn't have support
for emulating it yet.
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210409152154.198566-3-alexandru.elisei@arm.com
KVM sets up MDCR_EL2 to trap accesses to the SPE buffer and sampling
control registers and it relies on the fact that KVM injects an undefined
exception for unknown registers. This mechanism of injecting undefined
exceptions also prints a warning message for the host kernel; for example,
when a guest tries to access PMSIDR_EL1:
[ 2.691830] kvm [142]: Unsupported guest sys_reg access at: 80009e78 [800003c5]
[ 2.691830] { Op0( 3), Op1( 0), CRn( 9), CRm( 9), Op2( 7), func_read },
This is unnecessary, because KVM has explicitly configured trapping of
those registers and is well aware of their existence. Prevent the warning
by adding the SPE registers to the list of registers that KVM emulates.
The access function will inject the undefined exception.
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210409152154.198566-2-alexandru.elisei@arm.com
On vcpu reset, we expect all the registers to be brought back
to their initial state, which happens to be a bunch of zeroes.
However, some recent commit broke this, and is now leaving a bunch
of registers (such as the FP state) with whatever was left by the
guest. My bad.
Zero the reset of the state (32bit SPSRs and FPSIMD state).
Cc: stable@vger.kernel.org
Fixes: e47c2055c6 ("KVM: arm64: Make struct kvm_regs userspace-only")
Signed-off-by: Marc Zyngier <maz@kernel.org>
Although the KVM_ARM_VCPU_INIT documentation mention that the
registers are reset to their "initial values", it doesn't
describe what these values are.
Describe this state explicitly.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
CONFIG_ARM64_VHE was introduced with ARMv8.1 (some 7 years ago),
and has been enabled by default for almost all that time.
Given that newer systems that are VHE capable are finally becoming
available, and that some systems are even incapable of not running VHE,
drop the configuration altogether.
Anyone willing to stick to non-VHE on VHE hardware for obscure
reasons should use the 'kvm-arm.mode=nvhe' command-line option.
Suggested-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210408131010.1109027-4-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
It seems that the CPUs part of the SoC known as Apple M1 have the
terrible habit of being stuck with HCR_EL2.E2H==1, in violation
of the architecture.
Try and work around this deplorable state of affairs by detecting
the stuck bit early and short-circuit the nVHE dance. Additional
filtering code ensures that attempts at switching to nVHE from
the command-line are also ignored.
It is still unknown whether there are many more such nuggets
to be found...
Reported-by: Hector Martin <marcan@marcan.st>
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210408131010.1109027-3-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
Some CPUs are broken enough that some overrides need to be rejected
at the earliest opportunity. In some cases, that's right at cpu
feature override time.
Provide the necessary infrastructure to filter out overrides,
and to report such filtered out overrides to the core cpufeature code.
Acked-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210408131010.1109027-2-maz@kernel.org
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
The documentation build legitimately screams about the PTP
documentation table being misformated.
Fix it by adjusting the table width guides.
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Marc Zyngier <maz@kernel.org>
The kvmarm mailing list is moderated for non-subscriber, but that
was never advertised. Fix this with the hope that people will
eventually subscribe before posting, saving me the hassle of
letting their post through eventually.
Signed-off-by: Marc Zyngier <maz@kernel.org>
When a VCPU is created, the kvm_vcpu struct is initialized to zero in
kvm_vm_ioctl_create_vcpu(). On VHE systems, the first time
vcpu.arch.mdcr_el2 is loaded on hardware is in vcpu_load(), before it is
set to a sensible value in kvm_arm_setup_debug() later in the run loop. The
result is that KVM executes for a short time with MDCR_EL2 set to zero.
This has several unintended consequences:
* Setting MDCR_EL2.HPMN to 0 is constrained unpredictable according to ARM
DDI 0487G.a, page D13-3820. The behavior specified by the architecture
in this case is for the PE to behave as if MDCR_EL2.HPMN is set to a
value less than or equal to PMCR_EL0.N, which means that an unknown
number of counters are now disabled by MDCR_EL2.HPME, which is zero.
* The host configuration for the other debug features controlled by
MDCR_EL2 is temporarily lost. This has been harmless so far, as Linux
doesn't use the other fields, but that might change in the future.
Let's avoid both issues by initializing the VCPU's mdcr_el2 field in
kvm_vcpu_vcpu_first_run_init(), thus making sure that the MDCR_EL2 register
has a consistent value after each vcpu_load().
Fixes: d5a21bcc29 ("KVM: arm64: Move common VHE/non-VHE trap config in separate functions")
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210407144857.199746-3-alexandru.elisei@arm.com
Commit 21b6f32f94 ("KVM: arm64: guest debug, define API headers") added
the arm64 KVM_GUESTDBG_USE_HW flag for the KVM_SET_GUEST_DEBUG ioctl and
commit 834bf88726 ("KVM: arm64: enable KVM_CAP_SET_GUEST_DEBUG")
documented and implemented the flag functionality. Since its introduction,
at no point was the flag known by any name other than KVM_GUESTDBG_USE_HW
for the arm64 architecture, so refer to it as such in the documentation.
CC: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210407144857.199746-2-alexandru.elisei@arm.com
Currently, there is no mechanism to keep time sync between guest and host
in arm/arm64 virtualization environment. Time in guest will drift compared
with host after boot up as they may both use third party time sources
to correct their time respectively. The time deviation will be in order
of milliseconds. But in some scenarios,like in cloud environment, we ask
for higher time precision.
kvm ptp clock, which chooses the host clock source as a reference
clock to sync time between guest and host, has been adopted by x86
which takes the time sync order from milliseconds to nanoseconds.
This patch enables kvm ptp clock for arm/arm64 and improves clock sync precision
significantly.
Test result comparisons between with kvm ptp clock and without it in arm/arm64
are as follows. This test derived from the result of command 'chronyc
sources'. we should take more care of the last sample column which shows
the offset between the local clock and the source at the last measurement.
no kvm ptp in guest:
MS Name/IP address Stratum Poll Reach LastRx Last sample
========================================================================
^* dns1.synet.edu.cn 2 6 377 13 +1040us[+1581us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 21 +1040us[+1581us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 29 +1040us[+1581us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 37 +1040us[+1581us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 45 +1040us[+1581us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 53 +1040us[+1581us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 61 +1040us[+1581us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 4 -130us[ +796us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 12 -130us[ +796us] +/- 21ms
^* dns1.synet.edu.cn 2 6 377 20 -130us[ +796us] +/- 21ms
in host:
MS Name/IP address Stratum Poll Reach LastRx Last sample
========================================================================
^* 120.25.115.20 2 7 377 72 -470us[ -603us] +/- 18ms
^* 120.25.115.20 2 7 377 92 -470us[ -603us] +/- 18ms
^* 120.25.115.20 2 7 377 112 -470us[ -603us] +/- 18ms
^* 120.25.115.20 2 7 377 2 +872ns[-6808ns] +/- 17ms
^* 120.25.115.20 2 7 377 22 +872ns[-6808ns] +/- 17ms
^* 120.25.115.20 2 7 377 43 +872ns[-6808ns] +/- 17ms
^* 120.25.115.20 2 7 377 63 +872ns[-6808ns] +/- 17ms
^* 120.25.115.20 2 7 377 83 +872ns[-6808ns] +/- 17ms
^* 120.25.115.20 2 7 377 103 +872ns[-6808ns] +/- 17ms
^* 120.25.115.20 2 7 377 123 +872ns[-6808ns] +/- 17ms
The dns1.synet.edu.cn is the network reference clock for guest and
120.25.115.20 is the network reference clock for host. we can't get the
clock error between guest and host directly, but a roughly estimated value
will be in order of hundreds of us to ms.
with kvm ptp in guest:
chrony has been disabled in host to remove the disturb by network clock.
MS Name/IP address Stratum Poll Reach LastRx Last sample
========================================================================
* PHC0 0 3 377 8 -7ns[ +1ns] +/- 3ns
* PHC0 0 3 377 8 +1ns[ +16ns] +/- 3ns
* PHC0 0 3 377 6 -4ns[ -0ns] +/- 6ns
* PHC0 0 3 377 6 -8ns[ -12ns] +/- 5ns
* PHC0 0 3 377 5 +2ns[ +4ns] +/- 4ns
* PHC0 0 3 377 13 +2ns[ +4ns] +/- 4ns
* PHC0 0 3 377 12 -4ns[ -6ns] +/- 4ns
* PHC0 0 3 377 11 -8ns[ -11ns] +/- 6ns
* PHC0 0 3 377 10 -14ns[ -20ns] +/- 4ns
* PHC0 0 3 377 8 +4ns[ +5ns] +/- 4ns
The PHC0 is the ptp clock which choose the host clock as its source
clock. So we can see that the clock difference between host and guest
is in order of ns.
Cc: Mark Rutland <mark.rutland@arm.com>
Acked-by: Richard Cochran <richardcochran@gmail.com>
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-8-jianyong.wu@arm.com
System time snapshots are not conveying information about the current
clocksource which was used, but callers like the PTP KVM guest
implementation have the requirement to evaluate the clocksource type to
select the appropriate mechanism.
Introduce a clocksource id field in struct clocksource which is by default
set to CSID_GENERIC (0). Clocksource implementations can set that field to
a value which allows to identify the clocksource.
Store the clocksource id of the current clocksource in the
system_time_snapshot so callers can evaluate which clocksource was used to
take the snapshot and act accordingly.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Jianyong Wu <jianyong.wu@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20201209060932.212364-5-jianyong.wu@arm.com
Bring some improvements/rationalization over the first version
of the vgic_init selftests:
- ucall_init is moved in run_cpu()
- vcpu_args_set is not called as not needed
- whenever a helper is supposed to succeed, call the non "_" version
- helpers do not return -errno, instead errno is checked by the caller
- vm_gic struct is used whenever possible, as well as vm_gic_destroy
- _kvm_create_device takes an addition fd parameter
Signed-off-by: Eric Auger <eric.auger@redhat.com>
Suggested-by: Andrew Jones <drjones@redhat.com>
Reviewed-by: Andrew Jones <drjones@redhat.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210407135937.533141-1-eric.auger@redhat.com
We needn't retrieve the memory slot again in user_mem_abort() because
the corresponding memory slot has been passed from the caller. This
would save some CPU cycles. For example, the time used to write 1GB
memory, which is backed by 2MB hugetlb pages and write-protected, is
dropped by 6.8% from 928ms to 864ms.
Signed-off-by: Gavin Shan <gshan@redhat.com>
Reviewed-by: Keqian Zhu <zhukeqian1@huawei.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20210316041126.81860-4-gshan@redhat.com
