linux-kernel - [PATCH] kvm: fix wrong exception emulation in check

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Message-Id: <1297c0dd3f1bb47a6d089f850b629c7aa0247040.1629257115.git.houwenlong93@linux.alibaba.com>
Date:   Wed, 18 Aug 2021 11:36:31 +0800
From:   Hou Wenlong <houwenlong93@...ux.alibaba.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.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>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
        x86@...nel.org, "H. Peter Anvin" <hpa@...or.com>,
        Avi Kivity <avi@...hat.com>, linux-kernel@...r.kernel.org
Subject: [PATCH] kvm: fix wrong exception emulation in check_rdtsc

According to Intel's SDM Vol2 and AMD's APM Vol3, when
CR4.TSD is set, use rdtsc/rdtscp instruction above privilege
level 0 should trigger a #GP.

Fixes: d7eb82030699e ("KVM: SVM: Add intercept checks for remaining group7 instructions")
Signed-off-by: Hou Wenlong <houwenlong93@...ux.alibaba.com>
---
 arch/x86/kvm/emulate.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index 2837110e66ed..c589ac832265 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -4206,7 +4206,7 @@ static int check_rdtsc(struct x86_emulate_ctxt *ctxt)
 	u64 cr4 = ctxt->ops->get_cr(ctxt, 4);
 
 	if (cr4 & X86_CR4_TSD && ctxt->ops->cpl(ctxt))
-		return emulate_ud(ctxt);
+		return emulate_gp(ctxt, 0);
 
 	return X86EMUL_CONTINUE;
 }
-- 
2.31.1