From 0128116550acf52043a0aa5cca3caa85e3853aca Mon Sep 17 00:00:00 2001 From: Sean Christopherson Date: Wed, 9 Jun 2021 11:56:18 -0700 Subject: [PATCH] KVM: x86: Drop .post_leave_smm(), i.e. the manual post-RSM MMU reset Drop the .post_leave_smm() emulator callback, which at this point is just a wrapper to kvm_mmu_reset_context(). The manual context reset is unnecessary, because unlike enter_smm() which calls vendor MSR/CR helpers directly, em_rsm() bounces through the KVM helpers, e.g. kvm_set_cr4(), which are responsible for processing side effects. em_rsm() is already subtly relying on this behavior as it doesn't manually do kvm_update_cpuid_runtime(), e.g. to recognize CR4.OSXSAVE changes. Signed-off-by: Sean Christopherson Message-Id: <20210609185619.992058-9-seanjc@google.com> Signed-off-by: Paolo Bonzini --- arch/x86/kvm/emulate.c | 10 ++++++++-- arch/x86/kvm/kvm_emulate.h | 1 - arch/x86/kvm/x86.c | 6 ------ 3 files changed, 8 insertions(+), 9 deletions(-) diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c index 4996eec7aa79..83520a9f171e 100644 --- a/arch/x86/kvm/emulate.c +++ b/arch/x86/kvm/emulate.c @@ -2591,8 +2591,14 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt) if (ret != X86EMUL_CONTINUE) goto emulate_shutdown; - ctxt->ops->post_leave_smm(ctxt); - + /* + * Note, the ctxt->ops callbacks are responsible for handling side + * effects when writing MSRs and CRs, e.g. MMU context resets, CPUID + * runtime updates, etc... If that changes, e.g. this flow is moved + * out of the emulator to make it look more like enter_smm(), then + * those side effects need to be explicitly handled for both success + * and shutdown. + */ return X86EMUL_CONTINUE; emulate_shutdown: diff --git a/arch/x86/kvm/kvm_emulate.h b/arch/x86/kvm/kvm_emulate.h index 298bb0da7b97..3ee701b0ef10 100644 --- a/arch/x86/kvm/kvm_emulate.h +++ b/arch/x86/kvm/kvm_emulate.h @@ -233,7 +233,6 @@ struct x86_emulate_ops { void (*exiting_smm)(struct x86_emulate_ctxt *ctxt); int (*pre_leave_smm)(struct x86_emulate_ctxt *ctxt, const char *smstate); - void (*post_leave_smm)(struct x86_emulate_ctxt *ctxt); void (*triple_fault)(struct x86_emulate_ctxt *ctxt); int (*set_xcr)(struct x86_emulate_ctxt *ctxt, u32 index, u64 xcr); }; diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 1017d398e72d..9a268728399e 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -7222,11 +7222,6 @@ static int emulator_pre_leave_smm(struct x86_emulate_ctxt *ctxt, return static_call(kvm_x86_pre_leave_smm)(emul_to_vcpu(ctxt), smstate); } -static void emulator_post_leave_smm(struct x86_emulate_ctxt *ctxt) -{ - kvm_mmu_reset_context(emul_to_vcpu(ctxt)); -} - static void emulator_triple_fault(struct x86_emulate_ctxt *ctxt) { kvm_make_request(KVM_REQ_TRIPLE_FAULT, emul_to_vcpu(ctxt)); @@ -7280,7 +7275,6 @@ static const struct x86_emulate_ops emulate_ops = { .get_hflags = emulator_get_hflags, .exiting_smm = emulator_exiting_smm, .pre_leave_smm = emulator_pre_leave_smm, - .post_leave_smm = emulator_post_leave_smm, .triple_fault = emulator_triple_fault, .set_xcr = emulator_set_xcr, }; -- 2.11.0