KVM: SVM: enhance MOV CR intercept handler
Newer SVM implementations provide the GPR number in the VMCB, so
that the emulation path is no longer necesarry to handle CR
register access intercepts. Implement the handling in svm.c and
use it when the info is provided.
Signed-off-by: Andre Przywara <andre.przywara@amd.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 2830a73..5abaa5b2 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -2660,12 +2660,80 @@
return emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE;
}
+#define CR_VALID (1ULL << 63)
+
+static int cr_interception(struct vcpu_svm *svm)
+{
+ int reg, cr;
+ unsigned long val;
+ int err;
+
+ if (!static_cpu_has(X86_FEATURE_DECODEASSISTS))
+ return emulate_on_interception(svm);
+
+ if (unlikely((svm->vmcb->control.exit_info_1 & CR_VALID) == 0))
+ return emulate_on_interception(svm);
+
+ reg = svm->vmcb->control.exit_info_1 & SVM_EXITINFO_REG_MASK;
+ cr = svm->vmcb->control.exit_code - SVM_EXIT_READ_CR0;
+
+ err = 0;
+ if (cr >= 16) { /* mov to cr */
+ cr -= 16;
+ val = kvm_register_read(&svm->vcpu, reg);
+ switch (cr) {
+ case 0:
+ err = kvm_set_cr0(&svm->vcpu, val);
+ break;
+ case 3:
+ err = kvm_set_cr3(&svm->vcpu, val);
+ break;
+ case 4:
+ err = kvm_set_cr4(&svm->vcpu, val);
+ break;
+ case 8:
+ err = kvm_set_cr8(&svm->vcpu, val);
+ break;
+ default:
+ WARN(1, "unhandled write to CR%d", cr);
+ kvm_queue_exception(&svm->vcpu, UD_VECTOR);
+ return 1;
+ }
+ } else { /* mov from cr */
+ switch (cr) {
+ case 0:
+ val = kvm_read_cr0(&svm->vcpu);
+ break;
+ case 2:
+ val = svm->vcpu.arch.cr2;
+ break;
+ case 3:
+ val = svm->vcpu.arch.cr3;
+ break;
+ case 4:
+ val = kvm_read_cr4(&svm->vcpu);
+ break;
+ case 8:
+ val = kvm_get_cr8(&svm->vcpu);
+ break;
+ default:
+ WARN(1, "unhandled read from CR%d", cr);
+ kvm_queue_exception(&svm->vcpu, UD_VECTOR);
+ return 1;
+ }
+ kvm_register_write(&svm->vcpu, reg, val);
+ }
+ kvm_complete_insn_gp(&svm->vcpu, err);
+
+ return 1;
+}
+
static int cr0_write_interception(struct vcpu_svm *svm)
{
struct kvm_vcpu *vcpu = &svm->vcpu;
int r;
- r = emulate_instruction(&svm->vcpu, 0);
+ r = cr_interception(svm);
if (svm->nested.vmexit_rip) {
kvm_register_write(vcpu, VCPU_REGS_RIP, svm->nested.vmexit_rip);
@@ -2674,7 +2742,7 @@
svm->nested.vmexit_rip = 0;
}
- return r == EMULATE_DONE;
+ return r;
}
static int cr8_write_interception(struct vcpu_svm *svm)
@@ -2684,13 +2752,13 @@
u8 cr8_prev = kvm_get_cr8(&svm->vcpu);
/* instruction emulation calls kvm_set_cr8() */
- r = emulate_instruction(&svm->vcpu, 0);
+ r = cr_interception(svm);
if (irqchip_in_kernel(svm->vcpu.kvm)) {
clr_cr_intercept(svm, INTERCEPT_CR8_WRITE);
- return r == EMULATE_DONE;
+ return r;
}
if (cr8_prev <= kvm_get_cr8(&svm->vcpu))
- return r == EMULATE_DONE;
+ return r;
kvm_run->exit_reason = KVM_EXIT_SET_TPR;
return 0;
}
@@ -2933,14 +3001,14 @@
}
static int (*svm_exit_handlers[])(struct vcpu_svm *svm) = {
- [SVM_EXIT_READ_CR0] = emulate_on_interception,
- [SVM_EXIT_READ_CR3] = emulate_on_interception,
- [SVM_EXIT_READ_CR4] = emulate_on_interception,
- [SVM_EXIT_READ_CR8] = emulate_on_interception,
+ [SVM_EXIT_READ_CR0] = cr_interception,
+ [SVM_EXIT_READ_CR3] = cr_interception,
+ [SVM_EXIT_READ_CR4] = cr_interception,
+ [SVM_EXIT_READ_CR8] = cr_interception,
[SVM_EXIT_CR0_SEL_WRITE] = emulate_on_interception,
[SVM_EXIT_WRITE_CR0] = cr0_write_interception,
- [SVM_EXIT_WRITE_CR3] = emulate_on_interception,
- [SVM_EXIT_WRITE_CR4] = emulate_on_interception,
+ [SVM_EXIT_WRITE_CR3] = cr_interception,
+ [SVM_EXIT_WRITE_CR4] = cr_interception,
[SVM_EXIT_WRITE_CR8] = cr8_write_interception,
[SVM_EXIT_READ_DR0] = emulate_on_interception,
[SVM_EXIT_READ_DR1] = emulate_on_interception,
