linux-kernel - [PATCH 5.10 89/96] KVM: VMX: Use current VMCS to query WAITPKG support for MSR emulation

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Message-Id: <20210816125437.960970405@linuxfoundation.org>
Date:   Mon, 16 Aug 2021 15:02:39 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Sean Christopherson <seanjc@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Subject: [PATCH 5.10 89/96] KVM: VMX: Use current VMCS to query WAITPKG support for MSR emulation

From: Sean Christopherson <seanjc@...gle.com>

commit 7b9cae027ba3aaac295ae23a62f47876ed97da73 upstream.

Use the secondary_exec_controls_get() accessor in vmx_has_waitpkg() to
effectively get the controls for the current VMCS, as opposed to using
vmx->secondary_exec_controls, which is the cached value of KVM's desired
controls for vmcs01 and truly not reflective of any particular VMCS.

While the waitpkg control is not dynamic, i.e. vmcs01 will always hold
the same waitpkg configuration as vmx->secondary_exec_controls, the same
does not hold true for vmcs02 if the L1 VMM hides the feature from L2.
If L1 hides the feature _and_ does not intercept MSR_IA32_UMWAIT_CONTROL,
L2 could incorrectly read/write L1's virtual MSR instead of taking a #GP.

Fixes: 6e3ba4abcea5 ("KVM: vmx: Emulate MSR IA32_UMWAIT_CONTROL")
Cc: stable@...r.kernel.org
Signed-off-by: Sean Christopherson <seanjc@...gle.com>
Message-Id: <20210810171952.2758100-2-seanjc@...gle.com>
Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 arch/x86/kvm/vmx/vmx.h |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -488,7 +488,7 @@ static inline void decache_tsc_multiplie

 static inline bool vmx_has_waitpkg(struct vcpu_vmx *vmx)
 {
-	return vmx->secondary_exec_control &
+	return secondary_exec_controls_get(vmx) &
 		SECONDARY_EXEC_ENABLE_USR_WAIT_PAUSE;
 }