diff options
author | Sean Christopherson <seanjc@google.com> | 2023-08-25 04:36:20 +0300 |
---|---|---|
committer | Sean Christopherson <seanjc@google.com> | 2023-10-05 01:08:53 +0300 |
commit | aeb904f6b9f1de588cf3130dc8a2c458b236704e (patch) | |
tree | 0773fdadcdcf863edc4f9f64cdb45940f30abc0d /arch/x86/kvm | |
parent | bc3d7c5570a03ab45bde4bae83697c80900fb714 (diff) | |
download | linux-aeb904f6b9f1de588cf3130dc8a2c458b236704e.tar.xz |
KVM: x86: Refactor can_emulate_instruction() return to be more expressive
Refactor and rename can_emulate_instruction() to allow vendor code to
return more than true/false, e.g. to explicitly differentiate between
"retry", "fault", and "unhandleable". For now, just do the plumbing, a
future patch will expand SVM's implementation to signal outright failure
if KVM attempts EMULTYPE_SKIP on an SEV guest.
No functional change intended (or rather, none that are visible to the
guest or userspace).
Link: https://lore.kernel.org/r/20230825013621.2845700-4-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm')
-rw-r--r-- | arch/x86/kvm/svm/svm.c | 31 | ||||
-rw-r--r-- | arch/x86/kvm/vmx/vmx.c | 12 | ||||
-rw-r--r-- | arch/x86/kvm/x86.c | 15 |
3 files changed, 32 insertions, 26 deletions
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c index f36a6d819280..c4e700f945f8 100644 --- a/arch/x86/kvm/svm/svm.c +++ b/arch/x86/kvm/svm/svm.c @@ -364,8 +364,8 @@ static void svm_set_interrupt_shadow(struct kvm_vcpu *vcpu, int mask) svm->vmcb->control.int_state |= SVM_INTERRUPT_SHADOW_MASK; } -static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, - void *insn, int insn_len); +static int svm_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, + void *insn, int insn_len); static int __svm_skip_emulated_instruction(struct kvm_vcpu *vcpu, bool commit_side_effects) @@ -391,7 +391,7 @@ static int __svm_skip_emulated_instruction(struct kvm_vcpu *vcpu, * right thing and treats "can't emulate" as outright failure * for EMULTYPE_SKIP. */ - if (!svm_can_emulate_instruction(vcpu, EMULTYPE_SKIP, NULL, 0)) + if (svm_check_emulate_instruction(vcpu, EMULTYPE_SKIP, NULL, 0) != X86EMUL_CONTINUE) return 0; if (unlikely(!commit_side_effects)) @@ -4727,15 +4727,15 @@ static void svm_enable_smi_window(struct kvm_vcpu *vcpu) } #endif -static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, - void *insn, int insn_len) +static int svm_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, + void *insn, int insn_len) { bool smep, smap, is_user; u64 error_code; /* Emulation is always possible when KVM has access to all guest state. */ if (!sev_guest(vcpu->kvm)) - return true; + return X86EMUL_CONTINUE; /* #UD and #GP should never be intercepted for SEV guests. */ WARN_ON_ONCE(emul_type & (EMULTYPE_TRAP_UD | @@ -4747,14 +4747,14 @@ static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, * to guest register state. */ if (sev_es_guest(vcpu->kvm)) - return false; + return X86EMUL_RETRY_INSTR; /* * Emulation is possible if the instruction is already decoded, e.g. * when completing I/O after returning from userspace. */ if (emul_type & EMULTYPE_NO_DECODE) - return true; + return X86EMUL_CONTINUE; /* * Emulation is possible for SEV guests if and only if a prefilled @@ -4780,9 +4780,11 @@ static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, * success (and in practice it will work the vast majority of the time). */ if (unlikely(!insn)) { - if (!(emul_type & EMULTYPE_SKIP)) - kvm_queue_exception(vcpu, UD_VECTOR); - return false; + if (emul_type & EMULTYPE_SKIP) + return X86EMUL_RETRY_INSTR; + + kvm_queue_exception(vcpu, UD_VECTOR); + return X86EMUL_PROPAGATE_FAULT; } /* @@ -4793,7 +4795,7 @@ static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, * table used to translate CS:RIP resides in emulated MMIO. */ if (likely(insn_len)) - return true; + return X86EMUL_CONTINUE; /* * Detect and workaround Errata 1096 Fam_17h_00_0Fh. @@ -4851,6 +4853,7 @@ static bool svm_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, kvm_inject_gp(vcpu, 0); else kvm_make_request(KVM_REQ_TRIPLE_FAULT, vcpu); + return X86EMUL_PROPAGATE_FAULT; } resume_guest: @@ -4868,7 +4871,7 @@ resume_guest: * doesn't explicitly define "ignored", i.e. doing nothing and letting * the guest spin is technically "ignoring" the access. */ - return false; + return X86EMUL_RETRY_INSTR; } static bool svm_apic_init_signal_blocked(struct kvm_vcpu *vcpu) @@ -5028,7 +5031,7 @@ static struct kvm_x86_ops svm_x86_ops __initdata = { .vm_copy_enc_context_from = sev_vm_copy_enc_context_from, .vm_move_enc_context_from = sev_vm_move_enc_context_from, - .can_emulate_instruction = svm_can_emulate_instruction, + .check_emulate_instruction = svm_check_emulate_instruction, .apic_init_signal_blocked = svm_apic_init_signal_blocked, diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c index 72e3943f3693..4e453ba28320 100644 --- a/arch/x86/kvm/vmx/vmx.c +++ b/arch/x86/kvm/vmx/vmx.c @@ -1657,8 +1657,8 @@ static int vmx_rtit_ctl_check(struct kvm_vcpu *vcpu, u64 data) return 0; } -static bool vmx_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, - void *insn, int insn_len) +static int vmx_check_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, + void *insn, int insn_len) { /* * Emulation of instructions in SGX enclaves is impossible as RIP does @@ -1669,9 +1669,9 @@ static bool vmx_can_emulate_instruction(struct kvm_vcpu *vcpu, int emul_type, */ if (to_vmx(vcpu)->exit_reason.enclave_mode) { kvm_queue_exception(vcpu, UD_VECTOR); - return false; + return X86EMUL_PROPAGATE_FAULT; } - return true; + return X86EMUL_CONTINUE; } static int skip_emulated_instruction(struct kvm_vcpu *vcpu) @@ -5792,7 +5792,7 @@ static int handle_ept_misconfig(struct kvm_vcpu *vcpu) { gpa_t gpa; - if (!vmx_can_emulate_instruction(vcpu, EMULTYPE_PF, NULL, 0)) + if (vmx_check_emulate_instruction(vcpu, EMULTYPE_PF, NULL, 0)) return 1; /* @@ -8341,7 +8341,7 @@ static struct kvm_x86_ops vmx_x86_ops __initdata = { .enable_smi_window = vmx_enable_smi_window, #endif - .can_emulate_instruction = vmx_can_emulate_instruction, + .check_emulate_instruction = vmx_check_emulate_instruction, .apic_init_signal_blocked = vmx_apic_init_signal_blocked, .migrate_timers = vmx_migrate_timers, diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 9f18b06bbda6..104e6b4520a9 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7474,11 +7474,11 @@ int kvm_write_guest_virt_system(struct kvm_vcpu *vcpu, gva_t addr, void *val, } EXPORT_SYMBOL_GPL(kvm_write_guest_virt_system); -static int kvm_can_emulate_insn(struct kvm_vcpu *vcpu, int emul_type, - void *insn, int insn_len) +static int kvm_check_emulate_insn(struct kvm_vcpu *vcpu, int emul_type, + void *insn, int insn_len) { - return static_call(kvm_x86_can_emulate_instruction)(vcpu, emul_type, - insn, insn_len); + return static_call(kvm_x86_check_emulate_instruction)(vcpu, emul_type, + insn, insn_len); } int handle_ud(struct kvm_vcpu *vcpu) @@ -7488,8 +7488,10 @@ int handle_ud(struct kvm_vcpu *vcpu) int emul_type = EMULTYPE_TRAP_UD; char sig[5]; /* ud2; .ascii "kvm" */ struct x86_exception e; + int r; - if (unlikely(!kvm_can_emulate_insn(vcpu, emul_type, NULL, 0))) + r = kvm_check_emulate_insn(vcpu, emul_type, NULL, 0); + if (r != X86EMUL_CONTINUE) return 1; if (fep_flags && @@ -8871,7 +8873,8 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, struct x86_emulate_ctxt *ctxt = vcpu->arch.emulate_ctxt; bool writeback = true; - if (unlikely(!kvm_can_emulate_insn(vcpu, emulation_type, insn, insn_len))) + r = kvm_check_emulate_insn(vcpu, emulation_type, insn, insn_len); + if (r != X86EMUL_CONTINUE) return 1; vcpu->arch.l1tf_flush_l1d = true; |