KVM: x86: introduce ISA specific SMM entry/exit callbacks

Entering and exiting SMM may require ISA specific handling under certain
circumstances. This commit adds two new callbacks with empty implementations.
Actual functionality will be added in following commits.

* pre_enter_smm() is to be called when injecting an SMM, before any
  SMM related vcpu state has been changed
* pre_leave_smm() is to be called when emulating the RSM instruction,
  when the vcpu is in real mode and before any SMM related vcpu state
  has been restored

Signed-off-by: Ladi Prosek <lprosek@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index fa2558e120249e6c36e368e396d2c9e188c57056..ad38c5e918ecc97d02301f3b69e667569e960d27 100644 (file)
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -225,6 +225,8 @@ struct x86_emulate_ops {
 
        unsigned (*get_hflags)(struct x86_emulate_ctxt *ctxt);
        void (*set_hflags)(struct x86_emulate_ctxt *ctxt, unsigned hflags);
+       int (*pre_leave_smm)(struct x86_emulate_ctxt *ctxt, u64 smbase);
+
 };
 
 typedef u32 __attribute__((vector_size(16))) sse128_t;

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index c73e493adf0748108c31389ca62437267ea877e2..23a9a5339f3f82d3b25670092f55f7c1528d3e79 100644 (file)
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -1061,6 +1061,9 @@ struct kvm_x86_ops {
        void (*cancel_hv_timer)(struct kvm_vcpu *vcpu);
 
        void (*setup_mce)(struct kvm_vcpu *vcpu);
+
+       int (*pre_enter_smm)(struct kvm_vcpu *vcpu, char *smstate);
+       int (*pre_leave_smm)(struct kvm_vcpu *vcpu, u64 smbase);
 };
 
 struct kvm_arch_async_pf {

diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index d90cdc77e077354f1407235e6b73f2fda21c430c..8079d141792af91994421d15c19c26d3bd386c59 100644 (file)
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2591,6 +2591,15 @@ static int em_rsm(struct x86_emulate_ctxt *ctxt)
        ctxt->ops->set_msr(ctxt, MSR_EFER, efer);
 
        smbase = ctxt->ops->get_smbase(ctxt);
+
+       /*
+        * Give pre_leave_smm() a chance to make ISA-specific changes to the
+        * vCPU state (e.g. enter guest mode) before loading state from the SMM
+        * state-save area.
+        */
+       if (ctxt->ops->pre_leave_smm(ctxt, smbase))
+               return X86EMUL_UNHANDLEABLE;
+
        if (emulator_has_longmode(ctxt))
                ret = rsm_load_state_64(ctxt, smbase + 0x8000);
        else

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 84f18634d87cd23558344f3e337b84715d4a156f..c4e9b99d48d861ed91b2fc96dd43f97001e242c7 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -5401,6 +5401,18 @@ static void svm_setup_mce(struct kvm_vcpu *vcpu)
        vcpu->arch.mcg_cap &= 0x1ff;
 }
 
+static int svm_pre_enter_smm(struct kvm_vcpu *vcpu, char *smstate)
+{
+       /* TODO: Implement */
+       return 0;
+}
+
+static int svm_pre_leave_smm(struct kvm_vcpu *vcpu, u64 smbase)
+{
+       /* TODO: Implement */
+       return 0;
+}
+
 static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
        .cpu_has_kvm_support = has_svm,
        .disabled_by_bios = is_disabled,
@@ -5511,6 +5523,9 @@ static struct kvm_x86_ops svm_x86_ops __ro_after_init = {
        .deliver_posted_interrupt = svm_deliver_avic_intr,
        .update_pi_irte = svm_update_pi_irte,
        .setup_mce = svm_setup_mce,
+
+       .pre_enter_smm = svm_pre_enter_smm,
+       .pre_leave_smm = svm_pre_leave_smm,
 };
 
 static int __init svm_init(void)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index c9214e3a01dfeaf0cff6c18b0cdfd91361185cc3..1305bb65688b7740b1829a2c8778ab648c532615 100644 (file)
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -11916,6 +11916,18 @@ static void vmx_setup_mce(struct kvm_vcpu *vcpu)
                        ~FEATURE_CONTROL_LMCE;
 }
 
+static int vmx_pre_enter_smm(struct kvm_vcpu *vcpu, char *smstate)
+{
+       /* TODO: Implement */
+       return 0;
+}
+
+static int vmx_pre_leave_smm(struct kvm_vcpu *vcpu, u64 smbase)
+{
+       /* TODO: Implement */
+       return 0;
+}
+
 static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
        .cpu_has_kvm_support = cpu_has_kvm_support,
        .disabled_by_bios = vmx_disabled_by_bios,
@@ -12041,6 +12053,9 @@ static struct kvm_x86_ops vmx_x86_ops __ro_after_init = {
 #endif
 
        .setup_mce = vmx_setup_mce,
+
+       .pre_enter_smm = vmx_pre_enter_smm,
+       .pre_leave_smm = vmx_pre_leave_smm,
 };
 
 static int __init vmx_init(void)

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 4ac261000e7e616e0f5ebf53b7273b7f370b4477..9e85a69ccb124dd212176dd4546bd71aef96f888 100644 (file)
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -5281,6 +5281,11 @@ static void emulator_set_hflags(struct x86_emulate_ctxt *ctxt, unsigned emul_fla
        kvm_set_hflags(emul_to_vcpu(ctxt), emul_flags);
 }
 
+static int emulator_pre_leave_smm(struct x86_emulate_ctxt *ctxt, u64 smbase)
+{
+       return kvm_x86_ops->pre_leave_smm(emul_to_vcpu(ctxt), smbase);
+}
+
 static const struct x86_emulate_ops emulate_ops = {
        .read_gpr            = emulator_read_gpr,
        .write_gpr           = emulator_write_gpr,
@@ -5322,6 +5327,7 @@ static const struct x86_emulate_ops emulate_ops = {
        .set_nmi_mask        = emulator_set_nmi_mask,
        .get_hflags          = emulator_get_hflags,
        .set_hflags          = emulator_set_hflags,
+       .pre_leave_smm       = emulator_pre_leave_smm,
 };
 
 static void toggle_interruptibility(struct kvm_vcpu *vcpu, u32 mask)
@@ -6647,13 +6653,20 @@ static void enter_smm(struct kvm_vcpu *vcpu)
        u32 cr0;
 
        trace_kvm_enter_smm(vcpu->vcpu_id, vcpu->arch.smbase, true);
-       vcpu->arch.hflags |= HF_SMM_MASK;
        memset(buf, 0, 512);
        if (guest_cpuid_has(vcpu, X86_FEATURE_LM))
                enter_smm_save_state_64(vcpu, buf);
        else
                enter_smm_save_state_32(vcpu, buf);
 
+       /*
+        * Give pre_enter_smm() a chance to make ISA-specific changes to the
+        * vCPU state (e.g. leave guest mode) after we've saved the state into
+        * the SMM state-save area.
+        */
+       kvm_x86_ops->pre_enter_smm(vcpu, buf);
+
+       vcpu->arch.hflags |= HF_SMM_MASK;
        kvm_vcpu_write_guest(vcpu, vcpu->arch.smbase + 0xfe00, buf, sizeof(buf));
 
        if (kvm_x86_ops->get_nmi_mask(vcpu))