KVM: SVM: Remove nested sel_cr0_write handling code

This patch removes all the old code which handled the nested
selective cr0 write intercepts. This code was only in place
as a work-around until the instruction emulator is capable
of doing the same. This is the case with this patch-set and
so the code can be removed.

Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 26 insertions, 52 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 5c6512dbac7c..779b09194f03 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -93,14 +93,6 @@ struct nested_state {
         /* A VMEXIT is required but not yet emulated */
         bool exit_required;
 
-        /*
-         * If we vmexit during an instruction emulation we need this to restore
-         * the l1 guest rip after the emulation
-         */
-        unsigned long vmexit_rip;
-        unsigned long vmexit_rsp;
-        unsigned long vmexit_rax;
-
         /* cache for intercepts of the guest */
         u32 intercept_cr;
         u32 intercept_dr;
@@ -1362,31 +1354,6 @@ static void svm_set_cr0(struct kvm_vcpu *vcpu, unsigned long cr0)
 {
         struct vcpu_svm *svm = to_svm(vcpu);
 
-        if (is_guest_mode(vcpu)) {
-                /*
-                 * We are here because we run in nested mode, the host kvm
-                 * intercepts cr0 writes but the l1 hypervisor does not.
-                 * But the L1 hypervisor may intercept selective cr0 writes.
-                 * This needs to be checked here.
-                 */
-                unsigned long old, new;
-
-                /* Remove bits that would trigger a real cr0 write intercept */
-                old = vcpu->arch.cr0 & SVM_CR0_SELECTIVE_MASK;
-                new = cr0 & SVM_CR0_SELECTIVE_MASK;
-
-                if (old == new) {
-                        /* cr0 write with ts and mp unchanged */
-                        svm->vmcb->control.exit_code = SVM_EXIT_CR0_SEL_WRITE;
-                        if (nested_svm_exit_handled(svm) == NESTED_EXIT_DONE) {
-                                svm->nested.vmexit_rip = kvm_rip_read(vcpu);
-                                svm->nested.vmexit_rsp = kvm_register_read(vcpu, VCPU_REGS_RSP);
-                                svm->nested.vmexit_rax = kvm_register_read(vcpu, VCPU_REGS_RAX);
-                                return;
-                        }
-                }
-        }
-
 #ifdef CONFIG_X86_64
         if (vcpu->arch.efer & EFER_LME) {
                 if (!is_paging(vcpu) && (cr0 & X86_CR0_PG)) {
@@ -2673,6 +2640,29 @@ static int emulate_on_interception(struct vcpu_svm *svm)
         return emulate_instruction(&svm->vcpu, 0) == EMULATE_DONE;
 }
 
+bool check_selective_cr0_intercepted(struct vcpu_svm *svm, unsigned long val)
+{
+        unsigned long cr0 = svm->vcpu.arch.cr0;
+        bool ret = false;
+        u64 intercept;
+
+        intercept = svm->nested.intercept;
+
+        if (!is_guest_mode(&svm->vcpu) ||
+            (!(intercept & (1ULL << INTERCEPT_SELECTIVE_CR0))))
+                return false;
+
+        cr0 &= ~SVM_CR0_SELECTIVE_MASK;
+        val &= ~SVM_CR0_SELECTIVE_MASK;
+
+        if (cr0 ^ val) {
+                svm->vmcb->control.exit_code = SVM_EXIT_CR0_SEL_WRITE;
+                ret = (nested_svm_exit_handled(svm) == NESTED_EXIT_DONE);
+        }
+
+        return ret;
+}
+
 #define CR_VALID (1ULL << 63)
 
 static int cr_interception(struct vcpu_svm *svm)
@@ -2696,7 +2686,8 @@ static int cr_interception(struct vcpu_svm *svm)
                 val = kvm_register_read(&svm->vcpu, reg);
                 switch (cr) {
                 case 0:
-                        err = kvm_set_cr0(&svm->vcpu, val);
+                        if (!check_selective_cr0_intercepted(svm, val))
+                                err = kvm_set_cr0(&svm->vcpu, val);
                         break;
                 case 3:
                         err = kvm_set_cr3(&svm->vcpu, val);
@@ -2741,23 +2732,6 @@ static int cr_interception(struct vcpu_svm *svm)
         return 1;
 }
 
-static int cr0_write_interception(struct vcpu_svm *svm)
-{
-        struct kvm_vcpu *vcpu = &svm->vcpu;
-        int r;
-
-        r = cr_interception(svm);
-
-        if (svm->nested.vmexit_rip) {
-                kvm_register_write(vcpu, VCPU_REGS_RIP, svm->nested.vmexit_rip);
-                kvm_register_write(vcpu, VCPU_REGS_RSP, svm->nested.vmexit_rsp);
-                kvm_register_write(vcpu, VCPU_REGS_RAX, svm->nested.vmexit_rax);
-                svm->nested.vmexit_rip = 0;
-        }
-
-        return r;
-}
-
 static int dr_interception(struct vcpu_svm *svm)
 {
         int reg, dr;
@@ -3045,7 +3019,7 @@ static int (*svm_exit_handlers[])(struct vcpu_svm *svm) = {
         [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_CR0]                    = cr_interception,
         [SVM_EXIT_WRITE_CR3]                    = cr_interception,
         [SVM_EXIT_WRITE_CR4]                    = cr_interception,
         [SVM_EXIT_WRITE_CR8]                    = cr8_write_interception,