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| author | Sean Christopherson <seanjc@google.com> | 2023-01-24 23:49:01 +0000 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-01-26 18:03:42 -0800 |
| commit | e76ae52747a82a548742107b4100e90da41a624d (patch) | |
| tree | 52a26a3595bf153ee87d2ac4268add82f92236df /arch/x86/kvm/svm/svm.c | |
| parent | 8911ce66697e04ce7e92753dbf5645f748e27e12 (diff) | |
| download | linux-e76ae52747a82a548742107b4100e90da41a624d.tar.gz | |
KVM: x86/pmu: Gate all "unimplemented MSR" prints on report_ignored_msrs
Add helpers to print unimplemented MSR accesses and condition all such
prints on report_ignored_msrs, i.e. honor userspace's request to not
print unimplemented MSRs. Even though vcpu_unimpl() is ratelimited,
printing can still be problematic, e.g. if a print gets stalled when host
userspace is writing MSRs during live migration, an effective stall can
result in very noticeable disruption in the guest.
E.g. the profile below was taken while calling KVM_SET_MSRS on the PMU
counters while the PMU was disabled in KVM.
- 99.75% 0.00% [.] __ioctl
- __ioctl
- 99.74% entry_SYSCALL_64_after_hwframe
do_syscall_64
sys_ioctl
- do_vfs_ioctl
- 92.48% kvm_vcpu_ioctl
- kvm_arch_vcpu_ioctl
- 85.12% kvm_set_msr_ignored_check
svm_set_msr
kvm_set_msr_common
printk
vprintk_func
vprintk_default
vprintk_emit
console_unlock
call_console_drivers
univ8250_console_write
serial8250_console_write
uart_console_write
Reported-by: Aaron Lewis <aaronlewis@google.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Link: https://lore.kernel.org/r/20230124234905.3774678-3-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/svm/svm.c')
| -rw-r--r-- | arch/x86/kvm/svm/svm.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index d13cf53e7390..dd21e8b1a259 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -3015,8 +3015,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) break; case MSR_IA32_DEBUGCTLMSR: if (!lbrv) { - vcpu_unimpl(vcpu, "%s: MSR_IA32_DEBUGCTL 0x%llx, nop\n", - __func__, data); + kvm_pr_unimpl_wrmsr(vcpu, ecx, data); break; } if (data & DEBUGCTL_RESERVED_BITS) @@ -3045,7 +3044,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) case MSR_VM_CR: return svm_set_vm_cr(vcpu, data); case MSR_VM_IGNNE: - vcpu_unimpl(vcpu, "unimplemented wrmsr: 0x%x data 0x%llx\n", ecx, data); + kvm_pr_unimpl_wrmsr(vcpu, ecx, data); break; case MSR_AMD64_DE_CFG: { struct kvm_msr_entry msr_entry; |