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FAILED: patch "[PATCH] KVM: SVM: Truncate GPR value for DR and CR accesses in" failed to apply to 4.9-stable tree

PATCH [email protected] 2 participants 2 messages May 12, 2021 – Jun 7, 2021

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#0 lore raw

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From 0884335a2e653b8a045083aa1d57ce74269ac81d Mon Sep 17 00:00:00 2001
From: Sean Christopherson <[email protected]>
Date: Wed, 21 Apr 2021 19:21:22 -0700
Subject: [PATCH] KVM: SVM: Truncate GPR value for DR and CR accesses in
!64-bit mode

Drop bits 63:32 on loads/stores to/from DRs and CRs when the vCPU is not in 64-bit mode. The APM states bits 63:32 are dropped for both DRs and CRs:

In 64-bit mode, the operand size is fixed at 64 bits without the need for a REX prefix. In non-64-bit mode, the operand size is fixed at 32 bits and the upper 32 bits of the destination are forced to 0.

Fixes 7ff76d58a9dc ("KVM: SVM: enhance MOV CR intercept handler")
Fixes cae3797a4639 ("KVM: SVM: enhance mov DR intercept handler")
Cc [email protected]
Signed-off-by Sean Christopherson <[email protected]>

Message-Id: <[email protected]>

Signed-off-by Paolo Bonzini <[email protected]>
arch/x86/kvm/svm/svm.c +4 -4
index 301792542937..857bcf3a4cda 100644
@@ -2451,7 +2451,7 @@ static int cr_interception(struct kvm_vcpu *vcpu)
 	err = 0;
 	if (cr >= 16) { /* mov to cr */
 		cr -= 16;
-		val = kvm_register_read(vcpu, reg);
+		val = kvm_register_readl(vcpu, reg);
 		trace_kvm_cr_write(cr, val);
 		switch (cr) {
 		case 0:

@@ -2497,7 +2497,7 @@ static int cr_interception(struct kvm_vcpu *vcpu)
 			kvm_queue_exception(vcpu, UD_VECTOR);
 			return 1;
 		}
-		kvm_register_write(vcpu, reg, val);
+		kvm_register_writel(vcpu, reg, val);
 		trace_kvm_cr_read(cr, val);
 	}
 	return kvm_complete_insn_gp(vcpu, err);

@@ -2563,11 +2563,11 @@ static int dr_interception(struct kvm_vcpu *vcpu)
 	dr = svm->vmcb->control.exit_code - SVM_EXIT_READ_DR0;
 	if (dr >= 16) { /* mov to DRn  */
 		dr -= 16;
-		val = kvm_register_read(vcpu, reg);
+		val = kvm_register_readl(vcpu, reg);
 		err = kvm_set_dr(vcpu, dr, val);
 	} else {
 		kvm_get_dr(vcpu, dr, &val);
-		kvm_register_write(vcpu, reg, val);
+		kvm_register_writel(vcpu, reg, val);
 	}
 
 	return kvm_complete_insn_gp(vcpu, err);
#1 lore raw

Hi Greg,

Quoted 5 lines · On Wed, May 12, 2021 at 12:43:50PM +0200, [email protected] wrote:

The patch below does not apply to the 4.9-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

Here is the backport. Will also apply to 4.4-stable.

--
Regards
Sudip

From 89ffde7c080424821a70783961a7ab0dec90b9ea Mon Sep 17 00:00:00 2001
From: Sean Christopherson <[email protected]>
Date: Wed, 21 Apr 2021 19:21:22 -0700
Subject: [PATCH] KVM: SVM: Truncate GPR value for DR and CR accesses in
!64-bit mode

commit 0884335a2e653b8a045083aa1d57ce74269ac81d upstream.

Drop bits 63:32 on loads/stores to/from DRs and CRs when the vCPU is not in 64-bit mode. The APM states bits 63:32 are dropped for both DRs and CRs:

In 64-bit mode, the operand size is fixed at 64 bits without the need for a REX prefix. In non-64-bit mode, the operand size is fixed at 32 bits and the upper 32 bits of the destination are forced to 0.

Fixes 7ff76d58a9dc ("KVM: SVM: enhance MOV CR intercept handler")
Fixes cae3797a4639 ("KVM: SVM: enhance mov DR intercept handler")
Cc [email protected]
Signed-off-by Sean Christopherson <[email protected]>

Message-Id: <[email protected]>

Signed-off-by Paolo Bonzini <[email protected]>
[sudip: manual backport to old file]
Signed-off-by Sudip Mukherjee <[email protected]>
---
 arch/x86/kvm/svm.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)
arch/x86/kvm/svm.c +4 -4
index 29078eaf18c9..cbc7f177bbd8 100644
@@ -3412,7 +3412,7 @@ static int cr_interception(struct vcpu_svm *svm)
 	err = 0;
 	if (cr >= 16) { /* mov to cr */
 		cr -= 16;
-		val = kvm_register_read(&svm->vcpu, reg);
+		val = kvm_register_readl(&svm->vcpu, reg);
 		switch (cr) {
 		case 0:
 			if (!check_selective_cr0_intercepted(svm, val))

@@ -3457,7 +3457,7 @@ static int cr_interception(struct vcpu_svm *svm)
 			kvm_queue_exception(&svm->vcpu, UD_VECTOR);
 			return 1;
 		}
-		kvm_register_write(&svm->vcpu, reg, val);
+		kvm_register_writel(&svm->vcpu, reg, val);
 	}
 	kvm_complete_insn_gp(&svm->vcpu, err);
 

@@ -3489,13 +3489,13 @@ static int dr_interception(struct vcpu_svm *svm)
 	if (dr >= 16) { /* mov to DRn */
 		if (!kvm_require_dr(&svm->vcpu, dr - 16))
 			return 1;
-		val = kvm_register_read(&svm->vcpu, reg);
+		val = kvm_register_readl(&svm->vcpu, reg);
 		kvm_set_dr(&svm->vcpu, dr - 16, val);
 	} else {
 		if (!kvm_require_dr(&svm->vcpu, dr))
 			return 1;
 		kvm_get_dr(&svm->vcpu, dr, &val);
-		kvm_register_write(&svm->vcpu, reg, val);
+		kvm_register_writel(&svm->vcpu, reg, val);
 	}
 
 	skip_emulated_instruction(&svm->vcpu);
Signature · 1 line
2.30.2