From de3cd117ed2f6cb3317212f242a87ffca56c27ac Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Tue, 30 Apr 2019 10:36:17 -0700 Subject: KVM: x86: Omit caching logic for always-available GPRs Except for RSP and RIP, which are held in VMX's VMCS, GPRs are always treated "available and dirtly" on both VMX and SVM, i.e. are unconditionally loaded/saved immediately before/after VM-Enter/VM-Exit. Eliminating the unnecessary caching code reduces the size of KVM by a non-trivial amount, much of which comes from the most common code paths. E.g. on x86_64, kvm_emulate_cpuid() is reduced from 342 to 182 bytes and kvm_emulate_hypercall() from 1362 to 1143, with the total size of KVM dropping by ~1000 bytes. With CONFIG_RETPOLINE=y, the numbers are even more pronounced, e.g.: 353->182, 1418->1172 and well over 2000 bytes. Signed-off-by: Sean Christopherson Signed-off-by: Paolo Bonzini --- arch/x86/kvm/svm.c | 26 ++++++++++++-------------- 1 file changed, 12 insertions(+), 14 deletions(-) (limited to 'arch/x86/kvm/svm.c') diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c index 6e374a0e3bc3..38aef3439799 100644 --- a/arch/x86/kvm/svm.c +++ b/arch/x86/kvm/svm.c @@ -2091,7 +2091,7 @@ static void svm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event) init_vmcb(svm); kvm_cpuid(vcpu, &eax, &dummy, &dummy, &dummy, true); - kvm_register_write(vcpu, VCPU_REGS_RDX, eax); + kvm_rdx_write(vcpu, eax); if (kvm_vcpu_apicv_active(vcpu) && !init_event) avic_update_vapic_bar(svm, APIC_DEFAULT_PHYS_BASE); @@ -3388,7 +3388,7 @@ static int nested_svm_vmexit(struct vcpu_svm *svm) } else { (void)kvm_set_cr3(&svm->vcpu, hsave->save.cr3); } - kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, hsave->save.rax); + kvm_rax_write(&svm->vcpu, hsave->save.rax); kvm_register_write(&svm->vcpu, VCPU_REGS_RSP, hsave->save.rsp); kvm_register_write(&svm->vcpu, VCPU_REGS_RIP, hsave->save.rip); svm->vmcb->save.dr7 = 0; @@ -3496,7 +3496,7 @@ static void enter_svm_guest_mode(struct vcpu_svm *svm, u64 vmcb_gpa, kvm_mmu_reset_context(&svm->vcpu); svm->vmcb->save.cr2 = svm->vcpu.arch.cr2 = nested_vmcb->save.cr2; - kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, nested_vmcb->save.rax); + kvm_rax_write(&svm->vcpu, nested_vmcb->save.rax); kvm_register_write(&svm->vcpu, VCPU_REGS_RSP, nested_vmcb->save.rsp); kvm_register_write(&svm->vcpu, VCPU_REGS_RIP, nested_vmcb->save.rip); @@ -3787,11 +3787,11 @@ static int invlpga_interception(struct vcpu_svm *svm) { struct kvm_vcpu *vcpu = &svm->vcpu; - trace_kvm_invlpga(svm->vmcb->save.rip, kvm_register_read(&svm->vcpu, VCPU_REGS_RCX), - kvm_register_read(&svm->vcpu, VCPU_REGS_RAX)); + trace_kvm_invlpga(svm->vmcb->save.rip, kvm_rcx_read(&svm->vcpu), + kvm_rax_read(&svm->vcpu)); /* Let's treat INVLPGA the same as INVLPG (can be optimized!) */ - kvm_mmu_invlpg(vcpu, kvm_register_read(&svm->vcpu, VCPU_REGS_RAX)); + kvm_mmu_invlpg(vcpu, kvm_rax_read(&svm->vcpu)); svm->next_rip = kvm_rip_read(&svm->vcpu) + 3; return kvm_skip_emulated_instruction(&svm->vcpu); @@ -3799,7 +3799,7 @@ static int invlpga_interception(struct vcpu_svm *svm) static int skinit_interception(struct vcpu_svm *svm) { - trace_kvm_skinit(svm->vmcb->save.rip, kvm_register_read(&svm->vcpu, VCPU_REGS_RAX)); + trace_kvm_skinit(svm->vmcb->save.rip, kvm_rax_read(&svm->vcpu)); kvm_queue_exception(&svm->vcpu, UD_VECTOR); return 1; @@ -3813,7 +3813,7 @@ static int wbinvd_interception(struct vcpu_svm *svm) static int xsetbv_interception(struct vcpu_svm *svm) { u64 new_bv = kvm_read_edx_eax(&svm->vcpu); - u32 index = kvm_register_read(&svm->vcpu, VCPU_REGS_RCX); + u32 index = kvm_rcx_read(&svm->vcpu); if (kvm_set_xcr(&svm->vcpu, index, new_bv) == 0) { svm->next_rip = kvm_rip_read(&svm->vcpu) + 3; @@ -4209,7 +4209,7 @@ static int svm_get_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info) static int rdmsr_interception(struct vcpu_svm *svm) { - u32 ecx = kvm_register_read(&svm->vcpu, VCPU_REGS_RCX); + u32 ecx = kvm_rcx_read(&svm->vcpu); struct msr_data msr_info; msr_info.index = ecx; @@ -4221,10 +4221,8 @@ static int rdmsr_interception(struct vcpu_svm *svm) } else { trace_kvm_msr_read(ecx, msr_info.data); - kvm_register_write(&svm->vcpu, VCPU_REGS_RAX, - msr_info.data & 0xffffffff); - kvm_register_write(&svm->vcpu, VCPU_REGS_RDX, - msr_info.data >> 32); + kvm_rax_write(&svm->vcpu, msr_info.data & 0xffffffff); + kvm_rdx_write(&svm->vcpu, msr_info.data >> 32); svm->next_rip = kvm_rip_read(&svm->vcpu) + 2; return kvm_skip_emulated_instruction(&svm->vcpu); } @@ -4418,7 +4416,7 @@ static int svm_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr) static int wrmsr_interception(struct vcpu_svm *svm) { struct msr_data msr; - u32 ecx = kvm_register_read(&svm->vcpu, VCPU_REGS_RCX); + u32 ecx = kvm_rcx_read(&svm->vcpu); u64 data = kvm_read_edx_eax(&svm->vcpu); msr.data = data; -- cgit v1.2.3