KVM: x86: accessors for guest registers

As suggested by Avi, introduce accessors to read/write guest registers.
This simplifies the ->cache_regs/->decache_regs interface, and improves
register caching which is important for VMX, where the cost of
vmcs_read/vmcs_write is significant.

[avi: fix warnings]

Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Signed-off-by: Avi Kivity <avi@qumranet.com>

1 files changed, 23 insertions, 33 deletions

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 8233b86c778c..54b0bf33e21e 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -18,6 +18,7 @@
 #include "kvm_svm.h"
 #include "irq.h"
 #include "mmu.h"
+#include "kvm_cache_regs.h"
 
 #include <linux/module.h>
 #include <linux/kernel.h>
@@ -236,13 +237,11 @@ static void skip_emulated_instruction(struct kvm_vcpu *vcpu)
                 printk(KERN_DEBUG "%s: NOP\n", __func__);
                 return;
         }
-        if (svm->next_rip - svm->vmcb->save.rip > MAX_INST_SIZE)
-                printk(KERN_ERR "%s: ip 0x%llx next 0x%llx\n",
-                       __func__,
-                       svm->vmcb->save.rip,
-                       svm->next_rip);
+        if (svm->next_rip - kvm_rip_read(vcpu) > MAX_INST_SIZE)
+                printk(KERN_ERR "%s: ip 0x%lx next 0x%llx\n",
+                       __func__, kvm_rip_read(vcpu), svm->next_rip);
 
-        vcpu->arch.rip = svm->vmcb->save.rip = svm->next_rip;
+        kvm_rip_write(vcpu, svm->next_rip);
         svm->vmcb->control.int_state &= ~SVM_INTERRUPT_SHADOW_MASK;
 
         vcpu->arch.interrupt_window_open = 1;
@@ -581,6 +580,7 @@ static void init_vmcb(struct vcpu_svm *svm)
         save->dr7 = 0x400;
         save->rflags = 2;
         save->rip = 0x0000fff0;
+        svm->vcpu.arch.regs[VCPU_REGS_RIP] = save->rip;
 
         /*
          * cr0 val on cpu init should be 0x60000010, we enable cpu
@@ -615,10 +615,12 @@ static int svm_vcpu_reset(struct kvm_vcpu *vcpu)
         init_vmcb(svm);
 
         if (vcpu->vcpu_id != 0) {
-                svm->vmcb->save.rip = 0;
+                kvm_rip_write(vcpu, 0);
                 svm->vmcb->save.cs.base = svm->vcpu.arch.sipi_vector << 12;
                 svm->vmcb->save.cs.selector = svm->vcpu.arch.sipi_vector << 8;
         }
+        vcpu->arch.regs_avail = ~0;
+        vcpu->arch.regs_dirty = ~0;
 
         return 0;
 }
@@ -721,23 +723,6 @@ static void svm_vcpu_put(struct kvm_vcpu *vcpu)
         rdtscll(vcpu->arch.host_tsc);
 }
 
-static void svm_cache_regs(struct kvm_vcpu *vcpu)
-{
-        struct vcpu_svm *svm = to_svm(vcpu);
-
-        vcpu->arch.regs[VCPU_REGS_RAX] = svm->vmcb->save.rax;
-        vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
-        vcpu->arch.rip = svm->vmcb->save.rip;
-}
-
-static void svm_decache_regs(struct kvm_vcpu *vcpu)
-{
-        struct vcpu_svm *svm = to_svm(vcpu);
-        svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX];
-        svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP];
-        svm->vmcb->save.rip = vcpu->arch.rip;
-}
-
 static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)
 {
         return to_svm(vcpu)->vmcb->save.rflags;
@@ -1139,14 +1124,14 @@ static int nop_on_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 
 static int halt_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
-        svm->next_rip = svm->vmcb->save.rip + 1;
+        svm->next_rip = kvm_rip_read(&svm->vcpu) + 1;
         skip_emulated_instruction(&svm->vcpu);
         return kvm_emulate_halt(&svm->vcpu);
 }
 
 static int vmmcall_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
-        svm->next_rip = svm->vmcb->save.rip + 3;
+        svm->next_rip = kvm_rip_read(&svm->vcpu) + 3;
         skip_emulated_instruction(&svm->vcpu);
         kvm_emulate_hypercall(&svm->vcpu);
         return 1;
@@ -1178,7 +1163,7 @@ static int task_switch_interception(struct vcpu_svm *svm,
 
 static int cpuid_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
-        svm->next_rip = svm->vmcb->save.rip + 2;
+        svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
         kvm_emulate_cpuid(&svm->vcpu);
         return 1;
 }
@@ -1273,9 +1258,9 @@ static int rdmsr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
                 KVMTRACE_3D(MSR_READ, &svm->vcpu, ecx, (u32)data,
                             (u32)(data >> 32), handler);
 
-                svm->vmcb->save.rax = data & 0xffffffff;
+                svm->vcpu.arch.regs[VCPU_REGS_RAX] = data & 0xffffffff;
                 svm->vcpu.arch.regs[VCPU_REGS_RDX] = data >> 32;
-                svm->next_rip = svm->vmcb->save.rip + 2;
+                svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
                 skip_emulated_instruction(&svm->vcpu);
         }
         return 1;
@@ -1359,13 +1344,13 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, unsigned ecx, u64 data)
 static int wrmsr_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run)
 {
         u32 ecx = svm->vcpu.arch.regs[VCPU_REGS_RCX];
-        u64 data = (svm->vmcb->save.rax & -1u)
+        u64 data = (svm->vcpu.arch.regs[VCPU_REGS_RAX] & -1u)
                 | ((u64)(svm->vcpu.arch.regs[VCPU_REGS_RDX] & -1u) << 32);
 
         KVMTRACE_3D(MSR_WRITE, &svm->vcpu, ecx, (u32)data, (u32)(data >> 32),
                     handler);
 
-        svm->next_rip = svm->vmcb->save.rip + 2;
+        svm->next_rip = kvm_rip_read(&svm->vcpu) + 2;
         if (svm_set_msr(&svm->vcpu, ecx, data))
                 kvm_inject_gp(&svm->vcpu, 0);
         else
@@ -1723,6 +1708,10 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
         u16 gs_selector;
         u16 ldt_selector;
 
+        svm->vmcb->save.rax = vcpu->arch.regs[VCPU_REGS_RAX];
+        svm->vmcb->save.rsp = vcpu->arch.regs[VCPU_REGS_RSP];
+        svm->vmcb->save.rip = vcpu->arch.regs[VCPU_REGS_RIP];
+
         pre_svm_run(svm);
 
         sync_lapic_to_cr8(vcpu);
@@ -1858,6 +1847,9 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
                 load_db_regs(svm->host_db_regs);
 
         vcpu->arch.cr2 = svm->vmcb->save.cr2;
+        vcpu->arch.regs[VCPU_REGS_RAX] = svm->vmcb->save.rax;
+        vcpu->arch.regs[VCPU_REGS_RSP] = svm->vmcb->save.rsp;
+        vcpu->arch.regs[VCPU_REGS_RIP] = svm->vmcb->save.rip;
 
         write_dr6(svm->host_dr6);
         write_dr7(svm->host_dr7);
@@ -1977,8 +1969,6 @@ static struct kvm_x86_ops svm_x86_ops = {
         .set_gdt = svm_set_gdt,
         .get_dr = svm_get_dr,
         .set_dr = svm_set_dr,
-        .cache_regs = svm_cache_regs,
-        .decache_regs = svm_decache_regs,
         .get_rflags = svm_get_rflags,
         .set_rflags = svm_set_rflags,