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 v4] KVM: emulate: Don't inject #GP when emulating RDMPC if CR0.PE=0
Date: Wed, 20 Oct 2021 01:52:31 -0700 [thread overview]
Message-ID: <1634719951-73285-1-git-send-email-wanpengli@tencent.com> (raw)
From: Wanpeng Li <wanpengli@tencent.com>
SDM mentioned that we should #GP for rdpmc if ECX is not valid or
(CR4.PCE is 0 and CPL is 1, 2, or 3 and CR0.PE is 1).
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.
Reviewed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Wanpeng Li <wanpengli@tencent.com>
---
v3 -> v4:
* add comments instead of pseudocode
v2 -> v3:
* add the missing 'S'
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:[~2021-10-20 8:53 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-20 8:52 Wanpeng Li [this message]
2021-10-20 9:01 ` Paolo Bonzini
2021-10-20 10:15 ` Wanpeng Li
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