[PATCH 19/50] KVM: VMX: Enable NMI with in-kernel irqchip

From: Avi Kivity
Date: Thu Jun 26 2008 - 08:44:32 EST

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From: Sheng Yang <sheng.yang@xxxxxxxxx>

Signed-off-by: Sheng Yang <sheng.yang@xxxxxxxxx>
Signed-off-by: Avi Kivity <avi@xxxxxxxxxxxx>
---
arch/x86/kvm/vmx.c | 124 +++++++++++++++++++++++++++++++++++++------
arch/x86/kvm/vmx.h | 12 ++++-
arch/x86/kvm/x86.c | 1 +
include/asm-x86/kvm_host.h | 1 +
4 files changed, 119 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index 96377bf..332ed24 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -264,6 +264,11 @@ static inline int cpu_has_vmx_vpid(void)
SECONDARY_EXEC_ENABLE_VPID);
}

+static inline int cpu_has_virtual_nmis(void)
+{
+ return vmcs_config.pin_based_exec_ctrl & PIN_BASED_VIRTUAL_NMIS;
+}
+
static int __find_msr_index(struct vcpu_vmx *vmx, u32 msr)
{
int i;
@@ -1088,7 +1093,7 @@ static __init int setup_vmcs_config(struct vmcs_config *vmcs_conf)
u32 _vmentry_control = 0;

min = PIN_BASED_EXT_INTR_MASK | PIN_BASED_NMI_EXITING;
- opt = 0;
+ opt = PIN_BASED_VIRTUAL_NMIS;
if (adjust_vmx_controls(min, opt, MSR_IA32_VMX_PINBASED_CTLS,
&_pin_based_exec_control) < 0)
return -EIO;
@@ -2130,6 +2135,13 @@ static void vmx_inject_irq(struct kvm_vcpu *vcpu, int irq)
irq | INTR_TYPE_EXT_INTR | INTR_INFO_VALID_MASK);
}

+static void vmx_inject_nmi(struct kvm_vcpu *vcpu)
+{
+ vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
+ INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK | NMI_VECTOR);
+ vcpu->arch.nmi_pending = 0;
+}
+
static void kvm_do_inject_irq(struct kvm_vcpu *vcpu)
{
int word_index = __ffs(vcpu->arch.irq_summary);
@@ -2653,6 +2665,19 @@ static int handle_ept_violation(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
return 1;
}

+static int handle_nmi_window(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
+{
+ u32 cpu_based_vm_exec_control;
+
+ /* clear pending NMI */
+ cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
+ cpu_based_vm_exec_control &= ~CPU_BASED_VIRTUAL_NMI_PENDING;
+ vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
+ ++vcpu->stat.nmi_window_exits;
+
+ return 1;
+}
+
/*
* The exit handlers return 1 if the exit was handled fully and guest execution
* may resume. Otherwise they set the kvm_run parameter to indicate what needs
@@ -2663,6 +2688,7 @@ static int (*kvm_vmx_exit_handlers[])(struct kvm_vcpu *vcpu,
[EXIT_REASON_EXCEPTION_NMI] = handle_exception,
[EXIT_REASON_EXTERNAL_INTERRUPT] = handle_external_interrupt,
[EXIT_REASON_TRIPLE_FAULT] = handle_triple_fault,
+ [EXIT_REASON_NMI_WINDOW] = handle_nmi_window,
[EXIT_REASON_IO_INSTRUCTION] = handle_io,
[EXIT_REASON_CR_ACCESS] = handle_cr,
[EXIT_REASON_DR_ACCESS] = handle_dr,
@@ -2750,17 +2776,52 @@ static void enable_irq_window(struct kvm_vcpu *vcpu)
vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
}

+static void enable_nmi_window(struct kvm_vcpu *vcpu)
+{
+ u32 cpu_based_vm_exec_control;
+
+ if (!cpu_has_virtual_nmis())
+ return;
+
+ cpu_based_vm_exec_control = vmcs_read32(CPU_BASED_VM_EXEC_CONTROL);
+ cpu_based_vm_exec_control |= CPU_BASED_VIRTUAL_NMI_PENDING;
+ vmcs_write32(CPU_BASED_VM_EXEC_CONTROL, cpu_based_vm_exec_control);
+}
+
+static int vmx_nmi_enabled(struct kvm_vcpu *vcpu)
+{
+ u32 guest_intr = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
+ return !(guest_intr & (GUEST_INTR_STATE_NMI |
+ GUEST_INTR_STATE_MOV_SS |
+ GUEST_INTR_STATE_STI));
+}
+
+static int vmx_irq_enabled(struct kvm_vcpu *vcpu)
+{
+ u32 guest_intr = vmcs_read32(GUEST_INTERRUPTIBILITY_INFO);
+ return (!(guest_intr & (GUEST_INTR_STATE_MOV_SS |
+ GUEST_INTR_STATE_STI)) &&
+ (vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF));
+}
+
+static void enable_intr_window(struct kvm_vcpu *vcpu)
+{
+ if (vcpu->arch.nmi_pending)
+ enable_nmi_window(vcpu);
+ else if (kvm_cpu_has_interrupt(vcpu))
+ enable_irq_window(vcpu);
+}
+
static void vmx_intr_assist(struct kvm_vcpu *vcpu)
{
struct vcpu_vmx *vmx = to_vmx(vcpu);
- u32 idtv_info_field, intr_info_field;
- int has_ext_irq, interrupt_window_open;
+ u32 idtv_info_field, intr_info_field, exit_intr_info_field;
int vector;

update_tpr_threshold(vcpu);

- has_ext_irq = kvm_cpu_has_interrupt(vcpu);
intr_info_field = vmcs_read32(VM_ENTRY_INTR_INFO_FIELD);
+ exit_intr_info_field = vmcs_read32(VM_EXIT_INTR_INFO);
idtv_info_field = vmx->idt_vectoring_info;
if (intr_info_field & INTR_INFO_VALID_MASK) {
if (idtv_info_field & INTR_INFO_VALID_MASK) {
@@ -2768,8 +2829,7 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
if (printk_ratelimit())
printk(KERN_ERR "Fault when IDT_Vectoring\n");
}
- if (has_ext_irq)
- enable_irq_window(vcpu);
+ enable_intr_window(vcpu);
return;
}
if (unlikely(idtv_info_field & INTR_INFO_VALID_MASK)) {
@@ -2779,30 +2839,56 @@ static void vmx_intr_assist(struct kvm_vcpu *vcpu)
u8 vect = idtv_info_field & VECTORING_INFO_VECTOR_MASK;

vmx_inject_irq(vcpu, vect);
- if (unlikely(has_ext_irq))
- enable_irq_window(vcpu);
+ enable_intr_window(vcpu);
return;
}

KVMTRACE_1D(REDELIVER_EVT, vcpu, idtv_info_field, handler);

- vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, idtv_info_field);
+ /*
+ * SDM 3: 25.7.1.2
+ * Clear bit "block by NMI" before VM entry if a NMI delivery
+ * faulted.
+ */
+ if ((idtv_info_field & VECTORING_INFO_TYPE_MASK)
+ == INTR_TYPE_NMI_INTR && cpu_has_virtual_nmis())
+ vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
+ vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
+ ~GUEST_INTR_STATE_NMI);
+
+ vmcs_write32(VM_ENTRY_INTR_INFO_FIELD, idtv_info_field
+ & ~INTR_INFO_RESVD_BITS_MASK);
vmcs_write32(VM_ENTRY_INSTRUCTION_LEN,
vmcs_read32(VM_EXIT_INSTRUCTION_LEN));

if (unlikely(idtv_info_field & INTR_INFO_DELIVER_CODE_MASK))
vmcs_write32(VM_ENTRY_EXCEPTION_ERROR_CODE,
vmcs_read32(IDT_VECTORING_ERROR_CODE));
- if (unlikely(has_ext_irq))
- enable_irq_window(vcpu);
+ enable_intr_window(vcpu);
return;
}
- if (!has_ext_irq)
+ if (cpu_has_virtual_nmis()) {
+ /*
+ * SDM 3: 25.7.1.2
+ * Re-set bit "block by NMI" before VM entry if vmexit caused by
+ * a guest IRET fault.
+ */
+ if ((exit_intr_info_field & INTR_INFO_UNBLOCK_NMI) &&
+ (exit_intr_info_field & INTR_INFO_VECTOR_MASK) != 8)
+ vmcs_write32(GUEST_INTERRUPTIBILITY_INFO,
+ vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) |
+ GUEST_INTR_STATE_NMI);
+ else if (vcpu->arch.nmi_pending) {
+ if (vmx_nmi_enabled(vcpu))
+ vmx_inject_nmi(vcpu);
+ enable_intr_window(vcpu);
+ return;
+ }
+
+ }
+ if (!kvm_cpu_has_interrupt(vcpu))
return;
- interrupt_window_open =
- ((vmcs_readl(GUEST_RFLAGS) & X86_EFLAGS_IF) &&
- (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0);
- if (interrupt_window_open) {
+ if (vmx_irq_enabled(vcpu)) {
vector = kvm_cpu_get_interrupt(vcpu);
vmx_inject_irq(vcpu, vector);
kvm_timer_intr_post(vcpu, vector);
@@ -2963,7 +3049,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
fixup_rmode_irq(vmx);

vcpu->arch.interrupt_window_open =
- (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) & 3) == 0;
+ (vmcs_read32(GUEST_INTERRUPTIBILITY_INFO) &
+ (GUEST_INTR_STATE_STI | GUEST_INTR_STATE_MOV_SS)) == 0;

asm("mov %0, %%ds; mov %0, %%es" : : "r"(__USER_DS));
vmx->launched = 1;
@@ -2971,7 +3058,8 @@ static void vmx_vcpu_run(struct kvm_vcpu *vcpu, struct kvm_run *kvm_run)
intr_info = vmcs_read32(VM_EXIT_INTR_INFO);

/* We need to handle NMIs before interrupts are enabled */
- if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == 0x200) { /* nmi */
+ if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == 0x200 &&
+ (intr_info & INTR_INFO_VALID_MASK)) {
KVMTRACE_0D(NMI, vcpu, handler);
asm("int $2");
}
diff --git a/arch/x86/kvm/vmx.h b/arch/x86/kvm/vmx.h
index 79d94c6..425a134 100644
--- a/arch/x86/kvm/vmx.h
+++ b/arch/x86/kvm/vmx.h
@@ -40,6 +40,7 @@
#define CPU_BASED_CR8_LOAD_EXITING 0x00080000
#define CPU_BASED_CR8_STORE_EXITING 0x00100000
#define CPU_BASED_TPR_SHADOW 0x00200000
+#define CPU_BASED_VIRTUAL_NMI_PENDING 0x00400000
#define CPU_BASED_MOV_DR_EXITING 0x00800000
#define CPU_BASED_UNCOND_IO_EXITING 0x01000000
#define CPU_BASED_USE_IO_BITMAPS 0x02000000
@@ -216,7 +217,7 @@ enum vmcs_field {
#define EXIT_REASON_TRIPLE_FAULT 2

#define EXIT_REASON_PENDING_INTERRUPT 7
-
+#define EXIT_REASON_NMI_WINDOW 8
#define EXIT_REASON_TASK_SWITCH 9
#define EXIT_REASON_CPUID 10
#define EXIT_REASON_HLT 12
@@ -251,7 +252,9 @@ enum vmcs_field {
#define INTR_INFO_VECTOR_MASK 0xff /* 7:0 */
#define INTR_INFO_INTR_TYPE_MASK 0x700 /* 10:8 */
#define INTR_INFO_DELIVER_CODE_MASK 0x800 /* 11 */
+#define INTR_INFO_UNBLOCK_NMI 0x1000 /* 12 */
#define INTR_INFO_VALID_MASK 0x80000000 /* 31 */
+#define INTR_INFO_RESVD_BITS_MASK 0x7ffff000

#define VECTORING_INFO_VECTOR_MASK INTR_INFO_VECTOR_MASK
#define VECTORING_INFO_TYPE_MASK INTR_INFO_INTR_TYPE_MASK
@@ -259,9 +262,16 @@ enum vmcs_field {
#define VECTORING_INFO_VALID_MASK INTR_INFO_VALID_MASK

#define INTR_TYPE_EXT_INTR (0 << 8) /* external interrupt */
+#define INTR_TYPE_NMI_INTR (2 << 8) /* NMI */
#define INTR_TYPE_EXCEPTION (3 << 8) /* processor exception */
#define INTR_TYPE_SOFT_INTR (4 << 8) /* software interrupt */

+/* GUEST_INTERRUPTIBILITY_INFO flags. */
+#define GUEST_INTR_STATE_STI 0x00000001
+#define GUEST_INTR_STATE_MOV_SS 0x00000002
+#define GUEST_INTR_STATE_SMI 0x00000004
+#define GUEST_INTR_STATE_NMI 0x00000008
+
/*
* Exit Qualifications for MOV for Control Register Access
*/
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index 2c308f0..cab5f92 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -72,6 +72,7 @@ struct kvm_stats_debugfs_item debugfs_entries[] = {
{ "mmio_exits", VCPU_STAT(mmio_exits) },
{ "signal_exits", VCPU_STAT(signal_exits) },
{ "irq_window", VCPU_STAT(irq_window_exits) },
+ { "nmi_window", VCPU_STAT(nmi_window_exits) },
{ "halt_exits", VCPU_STAT(halt_exits) },
{ "halt_wakeup", VCPU_STAT(halt_wakeup) },
{ "hypercalls", VCPU_STAT(hypercalls) },
diff --git a/include/asm-x86/kvm_host.h b/include/asm-x86/kvm_host.h
index b666219..bacb1e2 100644
--- a/include/asm-x86/kvm_host.h
+++ b/include/asm-x86/kvm_host.h
@@ -347,6 +347,7 @@ struct kvm_vcpu_stat {
u32 mmio_exits;
u32 signal_exits;
u32 irq_window_exits;
+ u32 nmi_window_exits;
u32 halt_exits;
u32 halt_wakeup;
u32 request_irq_exits;
--
1.5.6

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