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Subject[PATCH 2/9] KVM: SVM: Add checks for CRx read and write intercepts
Date
This patch add code to check for any CRx read, write, and
the selective-cr0 intercepts for instructions emulated in
software by KVM.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
---
arch/x86/kvm/svm.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++++++-
1 files changed, 72 insertions(+), 1 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index d1721c2..29f0491 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3622,7 +3622,78 @@ static void svm_fpu_deactivate(struct kvm_vcpu *vcpu)
static int svm_insn_intercepted(struct kvm_vcpu *vcpu,
struct x86_emulate_ctxt *ctxt)
{
- return X86EMUL_CONTINUE;
+ struct decode_cache *c = &ctxt->decode;
+ struct vcpu_svm *svm = to_svm(vcpu);
+ struct vmcb *vmcb = svm->vmcb;
+ int vmexit, ret;
+
+ if (!is_nested(svm))
+ return X86EMUL_CONTINUE;
+
+ ret = X86EMUL_CONTINUE;
+
+ if (!c->twobyte)
+ goto out;
+
+ switch (c->b) {
+ case 0x01:
+ /* 0x0f 0x01 and modrm_mod == 3 encodes special instructions */
+ if (c->modrm_mod == 3)
+ break;
+
+ switch (c->modrm_reg) {
+ case 0x04: /* SMSW */
+ vmcb->control.exit_code = SVM_EXIT_READ_CR0;
+ break;
+ case 0x06: { /* LMSW */
+ u64 cr0, val;
+
+ vmcb->control.exit_code = SVM_EXIT_WRITE_CR0;
+
+ if (svm->nested.intercept_cr_write & INTERCEPT_CR0_MASK)
+ break;
+
+ /* check for selective-cr0 special case */
+ cr0 = vcpu->arch.cr0 & ~SVM_CR0_SELECTIVE_MASK & 0xf;
+ val = c->src.val & ~SVM_CR0_SELECTIVE_MASK & 0xf;
+
+ if (cr0 ^ val)
+ vmcb->control.exit_code = SVM_EXIT_CR0_SEL_WRITE;
+
+ break;
+ }
+ }
+ case 0x06: /* CLTS */
+ vmcb->control.exit_code = SVM_EXIT_WRITE_CR0;
+ break;
+ case 0x20: /* CR read */
+ vmcb->control.exit_code = SVM_EXIT_READ_CR0 + c->modrm_reg;
+ break;
+ case 0x22: /* CR write */
+ vmcb->control.exit_code = SVM_EXIT_WRITE_CR0 + c->modrm_reg;
+ if (c->modrm_reg == 0 &&
+ !(svm->nested.intercept_cr_write & INTERCEPT_CR0_MASK)) {
+ /* check for selective-cr0 special case */
+ u64 cr0, val;
+
+ cr0 = vcpu->arch.cr0 & ~SVM_CR0_SELECTIVE_MASK;
+ val = c->src.val & ~SVM_CR0_SELECTIVE_MASK;
+
+ if (cr0 ^ val)
+ vmcb->control.exit_code = SVM_EXIT_CR0_SEL_WRITE;
+ }
+ break;
+ }
+
+ vmcb->control.next_rip = ctxt->eip;
+ vmexit = nested_svm_exit_handled(svm);
+
+ ret = (vmexit == NESTED_EXIT_DONE) ? X86EMUL_INTERCEPTED
+ : X86EMUL_CONTINUE;
+
+out:
+
+ return ret;
}

static struct kvm_x86_ops svm_x86_ops = {
--
1.7.1



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