KVM: x86 emulator: access GPRs on demand

[deliverable/linux.git] / arch / x86 / kvm / x86.c

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 42bbf4187d20c64febfc6609094fdb8cddd0cc30..e00050ce7a6aed214b2e49cc363e2619040d1d62 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -4313,7 +4313,19 @@ static void emulator_get_cpuid(struct x86_emulate_ctxt *ctxt,
        kvm_cpuid(emul_to_vcpu(ctxt), eax, ebx, ecx, edx);
 }
 
+static ulong emulator_read_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg)
+{
+       return kvm_register_read(emul_to_vcpu(ctxt), reg);
+}
+
+static void emulator_write_gpr(struct x86_emulate_ctxt *ctxt, unsigned reg, ulong val)
+{
+       kvm_register_write(emul_to_vcpu(ctxt), reg, val);
+}
+
 static struct x86_emulate_ops emulate_ops = {
+       .read_gpr            = emulator_read_gpr,
+       .write_gpr           = emulator_write_gpr,
        .read_std            = kvm_read_guest_virt_system,
        .write_std           = kvm_write_guest_virt_system,
        .fetch               = kvm_fetch_guest_virt,
@@ -4348,14 +4360,6 @@ static struct x86_emulate_ops emulate_ops = {
        .get_cpuid           = emulator_get_cpuid,
 };
 
-static void cache_all_regs(struct kvm_vcpu *vcpu)
-{
-       kvm_register_read(vcpu, VCPU_REGS_RAX);
-       kvm_register_read(vcpu, VCPU_REGS_RSP);
-       kvm_register_read(vcpu, VCPU_REGS_RIP);
-       vcpu->arch.regs_dirty = ~0;
-}
-
 static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
 {
        u32 int_shadow = kvm_x86_ops->get_interrupt_shadow(vcpu, mask);
@@ -4382,12 +4386,10 @@ static void inject_emulated_exception(struct kvm_vcpu *vcpu)
                kvm_queue_exception(vcpu, ctxt->exception.vector);
 }
 
-static void init_decode_cache(struct x86_emulate_ctxt *ctxt,
-                             const unsigned long *regs)
+static void init_decode_cache(struct x86_emulate_ctxt *ctxt)
 {
        memset(&ctxt->twobyte, 0,
-              (void *)&ctxt->regs - (void *)&ctxt->twobyte);
-       memcpy(ctxt->regs, regs, sizeof(ctxt->regs));
+              (void *)&ctxt->_regs - (void *)&ctxt->twobyte);
 
        ctxt->fetch.start = 0;
        ctxt->fetch.end = 0;
@@ -4402,14 +4404,6 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        int cs_db, cs_l;
 
-       /*
-        * TODO: fix emulate.c to use guest_read/write_register
-        * instead of direct ->regs accesses, can save hundred cycles
-        * on Intel for instructions that don't read/change RSP, for
-        * for example.
-        */
-       cache_all_regs(vcpu);
-
        kvm_x86_ops->get_cs_db_l_bits(vcpu, &cs_db, &cs_l);
 
        ctxt->eflags = kvm_get_rflags(vcpu);
@@ -4421,7 +4415,7 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
                                                          X86EMUL_MODE_PROT16;
        ctxt->guest_mode = is_guest_mode(vcpu);
 
-       init_decode_cache(ctxt, vcpu->arch.regs);
+       init_decode_cache(ctxt);
        vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
 }
 
@@ -4441,7 +4435,6 @@ int kvm_inject_realmode_interrupt(struct kvm_vcpu *vcpu, int irq, int inc_eip)
                return EMULATE_FAIL;
 
        ctxt->eip = ctxt->_eip;
-       memcpy(vcpu->arch.regs, ctxt->regs, sizeof ctxt->regs);
        kvm_rip_write(vcpu, ctxt->eip);
        kvm_set_rflags(vcpu, ctxt->eflags);
 
@@ -4599,7 +4592,7 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu,
           changes registers values  during IO operation */
        if (vcpu->arch.emulate_regs_need_sync_from_vcpu) {
                vcpu->arch.emulate_regs_need_sync_from_vcpu = false;
-               memcpy(ctxt->regs, vcpu->arch.regs, sizeof ctxt->regs);
+               emulator_invalidate_register_cache(ctxt);
        }
 
 restart:
@@ -4637,7 +4630,6 @@ restart:
                toggle_interruptibility(vcpu, ctxt->interruptibility);
                kvm_set_rflags(vcpu, ctxt->eflags);
                kvm_make_request(KVM_REQ_EVENT, vcpu);
-               memcpy(vcpu->arch.regs, ctxt->regs, sizeof ctxt->regs);
                vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
                kvm_rip_write(vcpu, ctxt->eip);
        } else
@@ -5591,8 +5583,7 @@ int kvm_arch_vcpu_ioctl_get_regs(struct kvm_vcpu *vcpu, struct kvm_regs *regs)
                 * that usually, but some bad designed PV devices (vmware
                 * backdoor interface) need this to work
                 */
-               struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
-               memcpy(vcpu->arch.regs, ctxt->regs, sizeof ctxt->regs);
+               emulator_writeback_register_cache(&vcpu->arch.emulate_ctxt);
                vcpu->arch.emulate_regs_need_sync_to_vcpu = false;
        }
        regs->rax = kvm_register_read(vcpu, VCPU_REGS_RAX);
@@ -5723,6 +5714,7 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
 {
        struct x86_emulate_ctxt *ctxt = &vcpu->arch.emulate_ctxt;
        int ret;
+       unsigned reg;
 
        init_emulate_ctxt(vcpu);
 
@@ -5732,7 +5724,6 @@ int kvm_task_switch(struct kvm_vcpu *vcpu, u16 tss_selector, int idt_index,
        if (ret)
                return EMULATE_FAIL;
 
-       memcpy(vcpu->arch.regs, ctxt->regs, sizeof ctxt->regs);
        kvm_rip_write(vcpu, ctxt->eip);
        kvm_set_rflags(vcpu, ctxt->eflags);
        kvm_make_request(KVM_REQ_EVENT, vcpu);