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Subject[PATCH 07/12] KVM: x86: stubs for SMM support
Date
This patch adds the interface between x86.c and the emulator: the
SMBASE register, a new emulator flag, the RSM instruction. It also
adds a new request bit that will be used by the KVM_SMI ioctl.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
--
RFC->v1: make SMBASE host-readable only
add support for latching an SMI
do not reset SMBASE on INIT
---
arch/x86/include/asm/kvm_emulate.h | 4 +++
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/include/asm/vmx.h | 1 +
arch/x86/kvm/emulate.c | 10 ++++++-
arch/x86/kvm/lapic.c | 4 ++-
arch/x86/kvm/svm.c | 1 +
arch/x86/kvm/vmx.c | 2 +-
arch/x86/kvm/x86.c | 54 +++++++++++++++++++++++++++++++++++++-
include/linux/kvm_host.h | 1 +
9 files changed, 74 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kvm_emulate.h b/arch/x86/include/asm/kvm_emulate.h
index 7410879a41f7..e16466ec473c 100644
--- a/arch/x86/include/asm/kvm_emulate.h
+++ b/arch/x86/include/asm/kvm_emulate.h
@@ -193,6 +193,8 @@ struct x86_emulate_ops {
int (*cpl)(struct x86_emulate_ctxt *ctxt);
int (*get_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong *dest);
int (*set_dr)(struct x86_emulate_ctxt *ctxt, int dr, ulong value);
+ u64 (*get_smbase)(struct x86_emulate_ctxt *ctxt);
+ void (*set_smbase)(struct x86_emulate_ctxt *ctxt, u64 smbase);
int (*set_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 data);
int (*get_msr)(struct x86_emulate_ctxt *ctxt, u32 msr_index, u64 *pdata);
int (*check_pmc)(struct x86_emulate_ctxt *ctxt, u32 pmc);
@@ -264,6 +266,8 @@ enum x86emul_mode {

/* These match some of the HF_* flags defined in kvm_host.h */
#define X86EMUL_GUEST_MASK (1 << 5) /* VCPU is in guest-mode */
+#define X86EMUL_SMM_MASK (1 << 6)
+#define X86EMUL_SMM_INSIDE_NMI_MASK (1 << 7)

struct x86_emulate_ctxt {
const struct x86_emulate_ops *ops;
diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index a1bef695dc99..fc05c7dda9f1 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -367,6 +367,7 @@ struct kvm_vcpu_arch {
int32_t apic_arb_prio;
int mp_state;
u64 ia32_misc_enable_msr;
+ u64 smbase;
bool tpr_access_reporting;
u64 ia32_xss;

diff --git a/arch/x86/include/asm/vmx.h b/arch/x86/include/asm/vmx.h
index da772edd19ab..e8f998114df0 100644
--- a/arch/x86/include/asm/vmx.h
+++ b/arch/x86/include/asm/vmx.h
@@ -108,6 +108,7 @@
#define VMX_MISC_PREEMPTION_TIMER_RATE_MASK 0x0000001f
#define VMX_MISC_SAVE_EFER_LMA 0x00000020
#define VMX_MISC_ACTIVITY_HLT 0x00000040
+#define VMX_MISC_IA32_SMBASE_MSR 0x00008000

/* VMCS Encodings */
enum vmcs_field {
diff --git a/arch/x86/kvm/emulate.c b/arch/x86/kvm/emulate.c
index e82a559df21a..c5a6a407afba 100644
--- a/arch/x86/kvm/emulate.c
+++ b/arch/x86/kvm/emulate.c
@@ -2262,6 +2262,14 @@ static int em_lseg(struct x86_emulate_ctxt *ctxt)
return rc;
}

+static int em_rsm(struct x86_emulate_ctxt *ctxt)
+{
+ if ((ctxt->emul_flags & X86EMUL_SMM_MASK) == 0)
+ return emulate_ud(ctxt);
+
+ return X86EMUL_UNHANDLEABLE;
+}
+
static void
setup_syscalls_segments(struct x86_emulate_ctxt *ctxt,
struct desc_struct *cs, struct desc_struct *ss)
@@ -4173,7 +4181,7 @@ static const struct opcode twobyte_table[256] = {
F(DstMem | SrcReg | Src2CL | ModRM, em_shld), N, N,
/* 0xA8 - 0xAF */
I(Stack | Src2GS, em_push_sreg), I(Stack | Src2GS, em_pop_sreg),
- DI(ImplicitOps, rsm),
+ II(No64 | EmulateOnUD | ImplicitOps, em_rsm, rsm),
F(DstMem | SrcReg | ModRM | BitOp | Lock | PageTable, em_bts),
F(DstMem | SrcReg | Src2ImmByte | ModRM, em_shrd),
F(DstMem | SrcReg | Src2CL | ModRM, em_shrd),
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c
index dc5b57bb1f76..fe26f2051979 100644
--- a/arch/x86/kvm/lapic.c
+++ b/arch/x86/kvm/lapic.c
@@ -799,7 +799,9 @@ static int __apic_accept_irq(struct kvm_lapic *apic, int delivery_mode,
break;

case APIC_DM_SMI:
- apic_debug("Ignoring guest SMI\n");
+ result = 1;
+ kvm_make_request(KVM_REQ_SMI, vcpu);
+ kvm_vcpu_kick(vcpu);
break;

case APIC_DM_NMI:
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 24282bc6580c..6afffb82513c 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -3394,6 +3394,7 @@ static int (*const svm_exit_handlers[])(struct vcpu_svm *svm) = {
[SVM_EXIT_MWAIT] = mwait_interception,
[SVM_EXIT_XSETBV] = xsetbv_interception,
[SVM_EXIT_NPF] = pf_interception,
+ [SVM_EXIT_RSM] = emulate_on_interception,
};

static void dump_vmcb(struct kvm_vcpu *vcpu)
diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index bf961951786a..121a653919c0 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -2504,7 +2504,7 @@ static void nested_vmx_setup_ctls_msrs(struct vcpu_vmx *vmx)
vmx->nested.nested_vmx_misc_low &= VMX_MISC_SAVE_EFER_LMA;
vmx->nested.nested_vmx_misc_low |=
VMX_MISC_EMULATED_PREEMPTION_TIMER_RATE |
- VMX_MISC_ACTIVITY_HLT;
+ VMX_MISC_ACTIVITY_HLT | VMX_MISC_IA32_SMBASE_MSR;
vmx->nested.nested_vmx_misc_high = 0;
}

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 8015c67a6d07..2bf5bc4ed00f 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -954,6 +954,7 @@ static u32 emulated_msrs[] = {
MSR_IA32_MISC_ENABLE,
MSR_IA32_MCG_STATUS,
MSR_IA32_MCG_CTL,
+ MSR_IA32_SMBASE,
};

static unsigned num_emulated_msrs;
@@ -2220,6 +2221,11 @@ int kvm_set_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_MISC_ENABLE:
vcpu->arch.ia32_misc_enable_msr = data;
break;
+ case MSR_IA32_SMBASE:
+ if (!msr_info->host_initiated)
+ return 1;
+ vcpu->arch.smbase = data;
+ break;
case MSR_KVM_WALL_CLOCK_NEW:
case MSR_KVM_WALL_CLOCK:
vcpu->kvm->arch.wall_clock = data;
@@ -2615,6 +2621,11 @@ int kvm_get_msr_common(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
case MSR_IA32_MISC_ENABLE:
msr_info->data = vcpu->arch.ia32_misc_enable_msr;
break;
+ case MSR_IA32_SMBASE:
+ if (!msr_info->host_initiated)
+ return 1;
+ msr_info->data = vcpu->arch.smbase;
+ break;
case MSR_IA32_PERF_STATUS:
/* TSC increment by tick */
msr_info->data = 1000ULL;
@@ -3039,6 +3050,8 @@ static int kvm_vcpu_ioctl_nmi(struct kvm_vcpu *vcpu)

static int kvm_vcpu_ioctl_smi(struct kvm_vcpu *vcpu)
{
+ kvm_make_request(KVM_REQ_SMI, vcpu);
+
return 0;
}

@@ -5059,6 +5072,20 @@ static int emulator_set_msr(struct x86_emulate_ctxt *ctxt,
return kvm_set_msr(emul_to_vcpu(ctxt), &msr);
}

+static u64 emulator_get_smbase(struct x86_emulate_ctxt *ctxt)
+{
+ struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
+
+ return vcpu->arch.smbase;
+}
+
+static void emulator_set_smbase(struct x86_emulate_ctxt *ctxt, u64 smbase)
+{
+ struct kvm_vcpu *vcpu = emul_to_vcpu(ctxt);
+
+ vcpu->arch.smbase = smbase;
+}
+
static int emulator_check_pmc(struct x86_emulate_ctxt *ctxt,
u32 pmc)
{
@@ -5144,6 +5171,8 @@ static const struct x86_emulate_ops emulate_ops = {
.cpl = emulator_get_cpl,
.get_dr = emulator_get_dr,
.set_dr = emulator_set_dr,
+ .get_smbase = emulator_get_smbase,
+ .set_smbase = emulator_set_smbase,
.set_msr = emulator_set_msr,
.get_msr = emulator_get_msr,
.check_pmc = emulator_check_pmc,
@@ -5206,6 +5235,8 @@ static void init_emulate_ctxt(struct kvm_vcpu *vcpu)
cs_db ? X86EMUL_MODE_PROT32 :
X86EMUL_MODE_PROT16;
BUILD_BUG_ON(HF_GUEST_MASK != X86EMUL_GUEST_MASK);
+ BUILD_BUG_ON(HF_SMM_MASK != X86EMUL_SMM_MASK);
+ BUILD_BUG_ON(HF_SMM_INSIDE_NMI_MASK != X86EMUL_SMM_INSIDE_NMI_MASK);
ctxt->emul_flags = vcpu->arch.hflags;

init_decode_cache(ctxt);
@@ -5377,6 +5408,13 @@ static int complete_emulated_pio(struct kvm_vcpu *vcpu);

void kvm_set_hflags(struct kvm_vcpu *vcpu, unsigned emul_flags)
{
+ if (is_smm(vcpu) && (emul_flags & HF_SMM_MASK) == 0) {
+ if (unlikely(vcpu->arch.smi_pending)) {
+ kvm_make_request(KVM_REQ_SMI, vcpu);
+ vcpu->arch.smi_pending = 0;
+ }
+ }
+
vcpu->arch.hflags = emul_flags;
}

@@ -6271,6 +6309,16 @@ static void process_nmi(struct kvm_vcpu *vcpu)
kvm_make_request(KVM_REQ_EVENT, vcpu);
}

+static void process_smi(struct kvm_vcpu *vcpu)
+{
+ if (is_smm(vcpu)) {
+ vcpu->arch.smi_pending = true;
+ return;
+ }
+
+ printk_once(KERN_DEBUG "Ignoring guest SMI\n");
+}
+
static void vcpu_scan_ioapic(struct kvm_vcpu *vcpu)
{
u64 eoi_exit_bitmap[4];
@@ -6377,6 +6425,8 @@ static int vcpu_enter_guest(struct kvm_vcpu *vcpu)
}
if (kvm_check_request(KVM_REQ_STEAL_UPDATE, vcpu))
record_steal_time(vcpu);
+ if (kvm_check_request(KVM_REQ_SMI, vcpu))
+ process_smi(vcpu);
if (kvm_check_request(KVM_REQ_NMI, vcpu))
process_nmi(vcpu);
if (kvm_check_request(KVM_REQ_PMU, vcpu))
@@ -7276,8 +7326,10 @@ void kvm_vcpu_reset(struct kvm_vcpu *vcpu, bool init_event)
kvm_async_pf_hash_reset(vcpu);
vcpu->arch.apf.halted = false;

- if (!init_event)
+ if (!init_event) {
kvm_pmu_reset(vcpu);
+ vcpu->arch.smbase = 0x30000;
+ }

memset(vcpu->arch.regs, 0, sizeof(vcpu->arch.regs));
vcpu->arch.regs_avail = ~0;
diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 2946ec3f1b81..19d09a08885b 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h
@@ -134,6 +134,7 @@ static inline bool is_error_page(struct page *page)
#define KVM_REQ_ENABLE_IBS 23
#define KVM_REQ_DISABLE_IBS 24
#define KVM_REQ_APIC_PAGE_RELOAD 25
+#define KVM_REQ_SMI 26

#define KVM_USERSPACE_IRQ_SOURCE_ID 0
#define KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID 1
--
1.8.3.1



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