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From: Sean Christopherson <seanjc@google.com>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: 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>,
	kvm@vger.kernel.org, linux-kernel@vger.kernel.org,
	Babu Moger <babu.moger@amd.com>,
	Joao Martins <joao.m.martins@oracle.com>,
	David Woodhouse <dwmw@amazon.co.uk>
Subject: [PATCH 4/9] KVM: VMX: Truncate GPR value for DR and CR reads in !64-bit mode
Date: Fri, 12 Feb 2021 17:05:13 -0800	[thread overview]
Message-ID: <20210213010518.1682691-5-seanjc@google.com> (raw)
In-Reply-To: <20210213010518.1682691-1-seanjc@google.com>

Drop bits 63:32 when storing a DR/CR to a GPR when the vCPU is not in
64-bit mode.  Per the SDM:

  The operand size for these instructions is always 32 bits in non-64-bit
  modes, regardless of the operand-size attribute.

CR8 technically isn't affected as CR8 isn't accessible outside of 64-bit
mode, but fix it up for consistency and to allow for future cleanup.

Fixes: 6aa8b732ca01 ("[PATCH] kvm: userspace interface")
Cc: stable@vger.kernel.org
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 arch/x86/kvm/vmx/vmx.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index e0a3a9be654b..115826a020ff 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -5067,12 +5067,12 @@ static int handle_cr(struct kvm_vcpu *vcpu)
 		case 3:
 			WARN_ON_ONCE(enable_unrestricted_guest);
 			val = kvm_read_cr3(vcpu);
-			kvm_register_write(vcpu, reg, val);
+			kvm_register_writel(vcpu, reg, val);
 			trace_kvm_cr_read(cr, val);
 			return kvm_skip_emulated_instruction(vcpu);
 		case 8:
 			val = kvm_get_cr8(vcpu);
-			kvm_register_write(vcpu, reg, val);
+			kvm_register_writel(vcpu, reg, val);
 			trace_kvm_cr_read(cr, val);
 			return kvm_skip_emulated_instruction(vcpu);
 		}
@@ -5145,7 +5145,7 @@ static int handle_dr(struct kvm_vcpu *vcpu)
 		unsigned long val;
 
 		kvm_get_dr(vcpu, dr, &val);
-		kvm_register_write(vcpu, reg, val);
+		kvm_register_writel(vcpu, reg, val);
 		err = 0;
 	} else {
 		err = kvm_set_dr(vcpu, dr, kvm_register_readl(vcpu, reg));
-- 
2.30.0.478.g8a0d178c01-goog


  parent reply	other threads:[~2021-02-13  1:07 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-13  1:05 [PATCH 0/9] KVM: x86: Fixes for (benign?) truncation bugs Sean Christopherson
2021-02-13  1:05 ` [PATCH 1/9] KVM: x86: Remove emulator's broken checks on CR0/CR3/CR4 loads Sean Christopherson
2021-02-13  1:05 ` [PATCH 2/9] KVM: x86: Check CR3 GPA for validity regardless of vCPU mode Sean Christopherson
2021-02-13  1:05 ` [PATCH 3/9] KVM: SVM: Truncate GPR value for DR and CR accesses in !64-bit mode Sean Christopherson
2021-02-13  1:05 ` Sean Christopherson [this message]
2021-02-13  1:05 ` [PATCH 5/9] KVM: nVMX: Truncate bits 63:32 of VMCS field on nested check in !64-bit Sean Christopherson
2021-02-13  1:05 ` [PATCH 6/9] KVM: nVMX: Truncate base/index GPR value on address calc " Sean Christopherson
2021-02-13  1:05 ` [PATCH 7/9] KVM: x86/xen: Drop RAX[63:32] when processing hypercall Sean Christopherson
2021-02-13  1:05 ` [PATCH 8/9] KVM: SVM: Use default rAX size for INVLPGA emulation Sean Christopherson
2021-02-13  1:05 ` [PATCH 9/9] KVM: x86: Rename GPR accessors to make mode-aware variants the defaults Sean Christopherson

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