From: Wanpeng Li <kernellwp@gmail.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Paolo Bonzini <pbonzini@redhat.com>,
Sean Christopherson <seanjc@google.com>,
Vitaly Kuznetsov <vkuznets@redhat.com>,
Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>
Subject: [PATCH v2 1/3] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0
Date: Sat, 9 Oct 2021 02:08:50 -0700 [thread overview]
Message-ID: <1633770532-23664-1-git-send-email-wanpengli@tencent.com> (raw)
From: Wanpeng Li <wanpengli@tencent.com>
DM mentioned that, RDPMC:
IF (((CR4.PCE = 1) or (CPL = 0) or (CR0.PE = 0)) and (ECX indicates a supported counter))
THEN
EAX := counter[31:0];
EDX := ZeroExtend(counter[MSCB:32]);
ELSE (* ECX is not valid or CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1 *)
#GP(0);
FI;
Let's add the CR0.PE is 1 checking to rdpmc emulate, though this isn't
strictly necessary since it's impossible for CPL to be >0 if CR0.PE=0.
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
v1 -> v2:
* update patch description
arch/x86/kvm/emulate.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 9a144ca8e146..ab7ec569e8c9 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4213,6 +4213,7 @@ static int check_rdtsc(struct x86_emulate_ctxt *ctxt)
static int check_rdpmc(struct x86_emulate_ctxt *ctxt)
{
u64 cr4 = ctxt->ops->get_cr(ctxt, 4);
+ u64 cr0 = ctxt->ops->get_cr(ctxt, 0);
u64 rcx = reg_read(ctxt, VCPU_REGS_RCX);
/*
@@ -4222,7 +4223,7 @@ static int check_rdpmc(struct x86_emulate_ctxt *ctxt)
if (enable_vmware_backdoor && is_vmware_backdoor_pmc(rcx))
return X86EMUL_CONTINUE;
- if ((!(cr4 & X86_CR4_PCE) && ctxt->ops->cpl(ctxt)) ||
+ if ((!(cr4 & X86_CR4_PCE) && ctxt->ops->cpl(ctxt) && (cr0 & X86_CR0_PE)) ||
ctxt->ops->check_pmc(ctxt, rcx))
return emulate_gp(ctxt, 0);
--
2.25.1
next reply other threads:[~2021-10-09 9:09 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-09 9:08 Wanpeng Li [this message]
2021-10-09 9:08 ` [PATCH v2 2/3] KVM: vPMU: Fill get_msr MSR_CORE_PERF_GLOBAL_OVF_CTRL w/ 0 Wanpeng Li
2021-10-09 9:08 ` [PATCH v2 3/3] KVM: vCPU kick tax cut for running vCPU Wanpeng Li
2021-10-15 23:26 ` Sean Christopherson
2021-10-16 2:48 ` Wanpeng Li
2021-10-15 23:20 ` [PATCH v2 1/3] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0 Sean Christopherson
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