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Message-Id: <20210827005718.585190-8-seanjc@google.com>
Date: Thu, 26 Aug 2021 17:57:10 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Will Deacon <will@...nel.org>, Mark Rutland <mark.rutland@....com>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...hat.com>,
Arnaldo Carvalho de Melo <acme@...nel.org>,
Catalin Marinas <catalin.marinas@....com>,
Marc Zyngier <maz@...nel.org>, Guo Ren <guoren@...nel.org>,
Nick Hu <nickhu@...estech.com>,
Greentime Hu <green.hu@...il.com>,
Vincent Chen <deanbo422@...il.com>,
Paul Walmsley <paul.walmsley@...ive.com>,
Palmer Dabbelt <palmer@...belt.com>,
Albert Ou <aou@...s.berkeley.edu>,
Thomas Gleixner <tglx@...utronix.de>,
Borislav Petkov <bp@...en8.de>, x86@...nel.org,
Paolo Bonzini <pbonzini@...hat.com>,
Boris Ostrovsky <boris.ostrovsky@...cle.com>,
Juergen Gross <jgross@...e.com>
Cc: Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
Jiri Olsa <jolsa@...hat.com>,
Namhyung Kim <namhyung@...nel.org>,
James Morse <james.morse@....com>,
Alexandru Elisei <alexandru.elisei@....com>,
Suzuki K Poulose <suzuki.poulose@....com>,
"H. Peter Anvin" <hpa@...or.com>,
Sean Christopherson <seanjc@...gle.com>,
Vitaly Kuznetsov <vkuznets@...hat.com>,
Wanpeng Li <wanpengli@...cent.com>,
Jim Mattson <jmattson@...gle.com>,
Joerg Roedel <joro@...tes.org>,
Stefano Stabellini <sstabellini@...nel.org>,
linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
linux-csky@...r.kernel.org, linux-riscv@...ts.infradead.org,
kvm@...r.kernel.org, xen-devel@...ts.xenproject.org,
Artem Kashkanov <artem.kashkanov@...el.com>,
Like Xu <like.xu.linux@...il.com>,
Zhu Lingshan <lingshan.zhu@...el.com>
Subject: [PATCH 07/15] KVM: Use dedicated flag to track if KVM is handling an
NMI from guest
Add a dedicated flag to detect the case where KVM's PMC overflow
callback was originally invoked in response to an NMI that arrived while
the guest was running. Using current_vcpu is less precise as IRQs also
set current_vcpu (though presumably KVM's callback should not be reached
in that case), and more importantly, this will allow dropping
current_vcpu as the perf callbacks can switch to kvm_running_vcpu now
that the perf callbacks are precisely registered, i.e. kvm_running_vcpu
doesn't need to be used to detect if a PMI arrived in the guest.
Fixes: dd60d217062f ("KVM: x86: Fix perf timer mode IP reporting")
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
arch/x86/include/asm/kvm_host.h | 3 +--
arch/x86/kvm/pmu.c | 2 +-
arch/x86/kvm/svm/svm.c | 2 +-
arch/x86/kvm/vmx/vmx.c | 2 +-
arch/x86/kvm/x86.c | 4 ++--
arch/x86/kvm/x86.h | 4 +++-
6 files changed, 9 insertions(+), 8 deletions(-)
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1ea4943a73d7..465b35736d9b 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -763,6 +763,7 @@ struct kvm_vcpu_arch {
unsigned nmi_pending; /* NMI queued after currently running handler */
bool nmi_injected; /* Trying to inject an NMI this entry */
bool smi_pending; /* SMI queued after currently running handler */
+ bool handling_nmi_from_guest;
struct kvm_mtrr mtrr_state;
u64 pat;
@@ -1874,8 +1875,6 @@ int kvm_skip_emulated_instruction(struct kvm_vcpu *vcpu);
int kvm_complete_insn_gp(struct kvm_vcpu *vcpu, int err);
void __kvm_request_immediate_exit(struct kvm_vcpu *vcpu);
-int kvm_is_in_guest(void);
-
void __user *__x86_set_memory_region(struct kvm *kvm, int id, gpa_t gpa,
u32 size);
bool kvm_vcpu_is_reset_bsp(struct kvm_vcpu *vcpu);
diff --git a/arch/x86/kvm/pmu.c b/arch/x86/kvm/pmu.c
index 0772bad9165c..2b8934b452ea 100644
--- a/arch/x86/kvm/pmu.c
+++ b/arch/x86/kvm/pmu.c
@@ -87,7 +87,7 @@ static void kvm_perf_overflow_intr(struct perf_event *perf_event,
* woken up. So we should wake it, but this is impossible from
* NMI context. Do it from irq work instead.
*/
- if (!kvm_is_in_guest())
+ if (!pmc->vcpu->arch.handling_nmi_from_guest)
irq_work_queue(&pmc_to_pmu(pmc)->irq_work);
else
kvm_make_request(KVM_REQ_PMI, pmc->vcpu);
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 1a70e11f0487..3fc6767e5fd8 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -3843,7 +3843,7 @@ static __no_kcsan fastpath_t svm_vcpu_run(struct kvm_vcpu *vcpu)
}
if (unlikely(svm->vmcb->control.exit_code == SVM_EXIT_NMI))
- kvm_before_interrupt(vcpu);
+ kvm_before_interrupt(vcpu, true);
kvm_load_host_xsave_state(vcpu);
stgi();
diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index f19d72136f77..f08980ef7c44 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -6344,7 +6344,7 @@ void vmx_do_interrupt_nmi_irqoff(unsigned long entry);
static void handle_interrupt_nmi_irqoff(struct kvm_vcpu *vcpu,
unsigned long entry)
{
- kvm_before_interrupt(vcpu);
+ kvm_before_interrupt(vcpu, entry == (unsigned long)asm_exc_nmi_noist);
vmx_do_interrupt_nmi_irqoff(entry);
kvm_after_interrupt(vcpu);
}
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index bc4ee6ea7752..d4d91944fde7 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -8267,7 +8267,7 @@ static void kvm_timer_init(void)
DEFINE_PER_CPU(struct kvm_vcpu *, current_vcpu);
EXPORT_PER_CPU_SYMBOL_GPL(current_vcpu);
-int kvm_is_in_guest(void)
+static int kvm_is_in_guest(void)
{
return __this_cpu_read(current_vcpu) != NULL;
}
@@ -9678,7 +9678,7 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
* interrupts on processors that implement an interrupt shadow, the
* stat.exits increment will do nicely.
*/
- kvm_before_interrupt(vcpu);
+ kvm_before_interrupt(vcpu, false);
local_irq_enable();
++vcpu->stat.exits;
local_irq_disable();
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index 5cedc0e8a5d5..4c5ba4128b38 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -395,9 +395,10 @@ static inline void kvm_unregister_perf_callbacks(void)
DECLARE_PER_CPU(struct kvm_vcpu *, current_vcpu);
-static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu)
+static inline void kvm_before_interrupt(struct kvm_vcpu *vcpu, bool is_nmi)
{
__this_cpu_write(current_vcpu, vcpu);
+ WRITE_ONCE(vcpu->arch.handling_nmi_from_guest, is_nmi);
kvm_register_perf_callbacks();
}
@@ -406,6 +407,7 @@ static inline void kvm_after_interrupt(struct kvm_vcpu *vcpu)
{
kvm_unregister_perf_callbacks();
+ WRITE_ONCE(vcpu->arch.handling_nmi_from_guest, false);
__this_cpu_write(current_vcpu, NULL);
}
--
2.33.0.259.gc128427fd7-goog
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