E@google.com Fixes: 8a76d7f25f8f ("KVM: x86: Add x86 callback for intercept check") Cc: stable@vger.kernel.org Cc: Jim Mattson Link: https://lore.kernel.org/r/20250715190638.1899116-1-seanjc@google.com Signed-off-by: Sean Christopherson [ is_guest_mode() was open coded ] Signed-off-by: Sasha Levin --- arch/x86/kvm/emulate.c | 11 ++++------- arch/x86/kvm/kvm_emulate.h | 2 +- arch/x86/kvm/x86.c | 9 ++++++++- 3 files changed, 13 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 98b25a7af8ce8..dae68691f4248 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -5452,12 +5452,11 @@ void init_decode_cache(struct x86_emulate_ctxt *ctxt) ctxt->mem_read.end = 0; } -int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) +int x86_emulate_insn(struct x86_emulate_ctxt *ctxt, bool check_intercepts) { const struct x86_emulate_ops *ops = ctxt->ops; int rc = X86EMUL_CONTINUE; int saved_dst_type = ctxt->dst.type; - unsigned emul_flags; ctxt->mem_read.pos = 0; @@ -5471,8 +5470,6 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) rc = emulate_ud(ctxt); goto done; } - - emul_flags = ctxt->ops->get_hflags(ctxt); if (unlikely(ctxt->d & (No64|Undefined|Sse|Mmx|Intercept|CheckPerm|Priv|Prot|String))) { if ((ctxt->mode == X86EMUL_MODE_PROT64 && (ctxt->d & No64)) || @@ -5506,7 +5503,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) fetch_possible_mmx_operand(&ctxt->dst); } - if (unlikely(emul_flags & X86EMUL_GUEST_MASK) && ctxt->intercept) { + if (unlikely(check_intercepts) && ctxt->intercept) { rc = emulator_check_intercept(ctxt, ctxt->intercept, X86_ICPT_PRE_EXCEPT); if (rc != X86EMUL_CONTINUE) @@ -5535,7 +5532,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) goto done; } - if (unlikely(emul_flags & X86EMUL_GUEST_MASK) && (ctxt->d & Intercept)) { + if (unlikely(check_intercepts) && (ctxt->d & Intercept)) { rc = emulator_check_intercept(ctxt, ctxt->intercept, X86_ICPT_POST_EXCEPT); if (rc != X86EMUL_CONTINUE) @@ -5589,7 +5586,7 @@ int x86_emulate_insn(struct x86_emulate_ctxt *ctxt) special_insn: - if (unlikely(emul_flags & X86EMUL_GUEST_MASK) && (ctxt->d & Intercept)) { + if (unlikely(check_intercepts) && (ctxt->d & Intercept)) { rc = emulator_check_intercept(ctxt, ctxt->intercept, X86_ICPT_POST_MEMACCESS); if (rc != X86EMUL_CONTINUE) diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index fb09cd22cb7f5..6507340513cdd 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -496,7 +496,7 @@ bool x86_page_table_writing_insn(struct x86_emulate_ctxt *ctxt); #define EMULATION_RESTART 1 #define EMULATION_INTERCEPTED 2 void init_decode_cache(struct x86_emulate_ctxt *ctxt); -int x86_emulate_insn(struct x86_emulate_ctxt *ctxt); +int x86_emulate_insn(struct x86_emulate_ctxt *ctxt, bool check_intercepts); int emulator_task_switch(struct x86_emulate_ctxt *ctxt, u16 tss_selector, int idt_index, int reason, bool has_error_code, u32 error_code); diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 2ba297da7bdec..648f80f73e66c 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -8209,7 +8209,14 @@ int x86_emulate_instruction(struct kvm_vcpu *vcpu, gpa_t cr2_or_gpa, ctxt->exception.address = 0; } - r = x86_emulate_insn(ctxt); + /* + * Check L1's instruction intercepts when emulating instructions for + * L2, unless KVM is re-emulating a previously decoded instruction, + * e.g. to complete userspace I/O, in which case KVM has already + * checked the intercepts. + */ + r = x86_emulate_insn(ctxt, is_guest_mode(vcpu) && + !(emulation_type & EMULTYPE_NO_DECODE)); if (r == EMULATION_INTERCEPTED) return 1; -- 2.51.0[PATCH 5.15.y] KVM: x86: Don't (re)check L1 intercepts when completing userspace I/OSasha Levin undefinedstable@vger.kernel.org undefined undefined undefined undefined