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From: Jim Mattson <jmattson@google.com>
To: kvm@vger.kernel.org, pbonzini@redhat.com
Cc: Jim Mattson <jmattson@google.com>,
	Sean Christopherson <seanjc@google.com>
Subject: [PATCH] KVM: VMX: Heed the 'msr' argument in msr_write_intercepted()
Date: Wed, 10 Aug 2022 14:30:50 -0700	[thread overview]
Message-ID: <20220810213050.2655000-1-jmattson@google.com> (raw)

Regardless of the 'msr' argument passed to the VMX version of
msr_write_intercepted(), the function always checks to see if a
specific MSR (IA32_SPEC_CTRL) is intercepted for write.  This behavior
seems unintentional and unexpected.

Modify the function so that it checks to see if the provided 'msr'
index is intercepted for write.

Fixes: 67f4b9969c30 ("KVM: nVMX: Handle dynamic MSR intercept toggling")
Cc: Sean Christopherson <seanjc@google.com>
Signed-off-by: Jim Mattson <jmattson@google.com>
---
 arch/x86/kvm/vmx/vmx.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index d7f8331d6f7e..c9b49a09e6b5 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -843,8 +843,7 @@ static bool msr_write_intercepted(struct vcpu_vmx *vmx, u32 msr)
 	if (!(exec_controls_get(vmx) & CPU_BASED_USE_MSR_BITMAPS))
 		return true;
 
-	return vmx_test_msr_bitmap_write(vmx->loaded_vmcs->msr_bitmap,
-					 MSR_IA32_SPEC_CTRL);
+	return vmx_test_msr_bitmap_write(vmx->loaded_vmcs->msr_bitmap, msr);
 }
 
 unsigned int __vmx_vcpu_run_flags(struct vcpu_vmx *vmx)
-- 
2.37.1.559.g78731f0fdb-goog


             reply	other threads:[~2022-08-10 21:31 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-08-10 21:30 Jim Mattson [this message]
2022-08-10 21:50 ` [PATCH] KVM: VMX: Heed the 'msr' argument in msr_write_intercepted() Sean Christopherson
2022-08-12  7:57 ` Paolo Bonzini

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