The patch below does not apply to the 5.12-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 stable@vger.kernel.org.

thanks,

greg k-h

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

From 0884335a2e653b8a045083aa1d57ce74269ac81d Mon Sep 17 00:00:00 2001

From: Sean Christopherson seanjc@google.com 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: stable@vger.kernel.org Signed-off-by: Sean Christopherson seanjc@google.com Message-Id: 20210422022128.3464144-4-seanjc@google.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com

diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index 301792542937..857bcf3a4cda 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -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);