lkml.org 
[lkml]   [2021]   [May]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] KVM: x86/pt: Do not inject TraceToPAPMI when guest PT isn't supported
Date
When a PT perf user is running in system-wide mode on the host,
the guest (w/ pt_mode=0) will warn about anonymous NMIs from
kvm_handle_intel_pt_intr():

[ 18.126444] Uhhuh. NMI received for unknown reason 10 on CPU 0.
[ 18.126447] Do you have a strange power saving mode enabled?
[ 18.126448] Dazed and confused, but trying to continue

In this case, these PMIs should be handled by the host PT handler().
When PT is used in guest-only mode, it's harmless to call host handler.

Fix: 8479e04e7d("KVM: x86: Inject PMI for KVM guest")
Signed-off-by: Like Xu <like.xu@linux.intel.com>
---
arch/x86/events/intel/core.c | 3 +--
arch/x86/kvm/x86.c | 3 +++
2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c
index 2521d03de5e0..2f09eb0853de 100644
--- a/arch/x86/events/intel/core.c
+++ b/arch/x86/events/intel/core.c
@@ -2853,8 +2853,7 @@ static int handle_pmi_common(struct pt_regs *regs, u64 status)
if (unlikely(perf_guest_cbs && perf_guest_cbs->is_in_guest() &&
perf_guest_cbs->handle_intel_pt_intr))
perf_guest_cbs->handle_intel_pt_intr();
- else
- intel_pt_interrupt();
+ intel_pt_interrupt();
}

/*
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 6529e2023147..6660f3948cea 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8087,6 +8087,9 @@ static void kvm_handle_intel_pt_intr(void)
{
struct kvm_vcpu *vcpu = __this_cpu_read(current_vcpu);

+ if (!guest_cpuid_has(vcpu, X86_FEATURE_INTEL_PT))
+ return;
+
kvm_make_request(KVM_REQ_PMI, vcpu);
__set_bit(MSR_CORE_PERF_GLOBAL_OVF_CTRL_TRACE_TOPA_PMI_BIT,
(unsigned long *)&vcpu->arch.pmu.global_status);
--
2.31.1
\
 
 \ /
  Last update: 2021-05-14 10:46    [W:0.034 / U:1.384 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site