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Diffstat (limited to 'arch/x86/kvm/svm.c')
-rw-r--r--arch/x86/kvm/svm.c126
1 files changed, 101 insertions, 25 deletions
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index c27ac6923a18..905ea6052517 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -36,6 +36,7 @@
#include <linux/slab.h>
#include <linux/amd-iommu.h>
#include <linux/hashtable.h>
+#include <linux/frame.h>
#include <asm/apic.h>
#include <asm/perf_event.h>
@@ -189,6 +190,7 @@ struct vcpu_svm {
struct nested_state nested;
bool nmi_singlestep;
+ u64 nmi_singlestep_guest_rflags;
unsigned int3_injected;
unsigned long int3_rip;
@@ -963,6 +965,18 @@ static void svm_disable_lbrv(struct vcpu_svm *svm)
set_msr_interception(msrpm, MSR_IA32_LASTINTTOIP, 0, 0);
}
+static void disable_nmi_singlestep(struct vcpu_svm *svm)
+{
+ svm->nmi_singlestep = false;
+ if (!(svm->vcpu.guest_debug & KVM_GUESTDBG_SINGLESTEP)) {
+ /* Clear our flags if they were not set by the guest */
+ if (!(svm->nmi_singlestep_guest_rflags & X86_EFLAGS_TF))
+ svm->vmcb->save.rflags &= ~X86_EFLAGS_TF;
+ if (!(svm->nmi_singlestep_guest_rflags & X86_EFLAGS_RF))
+ svm->vmcb->save.rflags &= ~X86_EFLAGS_RF;
+ }
+}
+
/* Note:
* This hash table is used to map VM_ID to a struct kvm_arch,
* when handling AMD IOMMU GALOG notification to schedule in
@@ -1272,7 +1286,8 @@ static void init_vmcb(struct vcpu_svm *svm)
}
-static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu, int index)
+static u64 *avic_get_physical_id_entry(struct kvm_vcpu *vcpu,
+ unsigned int index)
{
u64 *avic_physical_id_table;
struct kvm_arch *vm_data = &vcpu->kvm->arch;
@@ -1711,11 +1726,24 @@ static void svm_vcpu_unblocking(struct kvm_vcpu *vcpu)
static unsigned long svm_get_rflags(struct kvm_vcpu *vcpu)
{
- return to_svm(vcpu)->vmcb->save.rflags;
+ struct vcpu_svm *svm = to_svm(vcpu);
+ unsigned long rflags = svm->vmcb->save.rflags;
+
+ if (svm->nmi_singlestep) {
+ /* Hide our flags if they were not set by the guest */
+ if (!(svm->nmi_singlestep_guest_rflags & X86_EFLAGS_TF))
+ rflags &= ~X86_EFLAGS_TF;
+ if (!(svm->nmi_singlestep_guest_rflags & X86_EFLAGS_RF))
+ rflags &= ~X86_EFLAGS_RF;
+ }
+ return rflags;
}
static void svm_set_rflags(struct kvm_vcpu *vcpu, unsigned long rflags)
{
+ if (to_svm(vcpu)->nmi_singlestep)
+ rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF);
+
/*
* Any change of EFLAGS.VM is accompanied by a reload of SS
* (caused by either a task switch or an inter-privilege IRET),
@@ -1806,7 +1834,7 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
* AMD's VMCB does not have an explicit unusable field, so emulate it
* for cross vendor migration purposes by "not present"
*/
- var->unusable = !var->present || (var->type == 0);
+ var->unusable = !var->present;
switch (seg) {
case VCPU_SREG_TR:
@@ -1839,6 +1867,7 @@ static void svm_get_segment(struct kvm_vcpu *vcpu,
*/
if (var->unusable)
var->db = 0;
+ /* This is symmetric with svm_set_segment() */
var->dpl = to_svm(vcpu)->vmcb->save.cpl;
break;
}
@@ -1979,18 +2008,14 @@ static void svm_set_segment(struct kvm_vcpu *vcpu,
s->base = var->base;
s->limit = var->limit;
s->selector = var->selector;
- if (var->unusable)
- s->attrib = 0;
- else {
- s->attrib = (var->type & SVM_SELECTOR_TYPE_MASK);
- s->attrib |= (var->s & 1) << SVM_SELECTOR_S_SHIFT;
- s->attrib |= (var->dpl & 3) << SVM_SELECTOR_DPL_SHIFT;
- s->attrib |= (var->present & 1) << SVM_SELECTOR_P_SHIFT;
- s->attrib |= (var->avl & 1) << SVM_SELECTOR_AVL_SHIFT;
- s->attrib |= (var->l & 1) << SVM_SELECTOR_L_SHIFT;
- s->attrib |= (var->db & 1) << SVM_SELECTOR_DB_SHIFT;
- s->attrib |= (var->g & 1) << SVM_SELECTOR_G_SHIFT;
- }
+ s->attrib = (var->type & SVM_SELECTOR_TYPE_MASK);
+ s->attrib |= (var->s & 1) << SVM_SELECTOR_S_SHIFT;
+ s->attrib |= (var->dpl & 3) << SVM_SELECTOR_DPL_SHIFT;
+ s->attrib |= ((var->present & 1) && !var->unusable) << SVM_SELECTOR_P_SHIFT;
+ s->attrib |= (var->avl & 1) << SVM_SELECTOR_AVL_SHIFT;
+ s->attrib |= (var->l & 1) << SVM_SELECTOR_L_SHIFT;
+ s->attrib |= (var->db & 1) << SVM_SELECTOR_DB_SHIFT;
+ s->attrib |= (var->g & 1) << SVM_SELECTOR_G_SHIFT;
/*
* This is always accurate, except if SYSRET returned to a segment
@@ -1999,7 +2024,8 @@ static void svm_set_segment(struct kvm_vcpu *vcpu,
* would entail passing the CPL to userspace and back.
*/
if (seg == VCPU_SREG_SS)
- svm->vmcb->save.cpl = (s->attrib >> SVM_SELECTOR_DPL_SHIFT) & 3;
+ /* This is symmetric with svm_get_segment() */
+ svm->vmcb->save.cpl = (var->dpl & 3);
mark_dirty(svm->vmcb, VMCB_SEG);
}
@@ -2112,10 +2138,7 @@ static int db_interception(struct vcpu_svm *svm)
}
if (svm->nmi_singlestep) {
- svm->nmi_singlestep = false;
- if (!(svm->vcpu.guest_debug & KVM_GUESTDBG_SINGLESTEP))
- svm->vmcb->save.rflags &=
- ~(X86_EFLAGS_TF | X86_EFLAGS_RF);
+ disable_nmi_singlestep(svm);
}
if (svm->vcpu.guest_debug &
@@ -2370,8 +2393,8 @@ static void nested_svm_uninit_mmu_context(struct kvm_vcpu *vcpu)
static int nested_svm_check_permissions(struct vcpu_svm *svm)
{
- if (!(svm->vcpu.arch.efer & EFER_SVME)
- || !is_paging(&svm->vcpu)) {
+ if (!(svm->vcpu.arch.efer & EFER_SVME) ||
+ !is_paging(&svm->vcpu)) {
kvm_queue_exception(&svm->vcpu, UD_VECTOR);
return 1;
}
@@ -2381,7 +2404,7 @@ static int nested_svm_check_permissions(struct vcpu_svm *svm)
return 1;
}
- return 0;
+ return 0;
}
static int nested_svm_check_exception(struct vcpu_svm *svm, unsigned nr,
@@ -2534,6 +2557,31 @@ static int nested_svm_exit_handled_msr(struct vcpu_svm *svm)
return (value & mask) ? NESTED_EXIT_DONE : NESTED_EXIT_HOST;
}
+/* DB exceptions for our internal use must not cause vmexit */
+static int nested_svm_intercept_db(struct vcpu_svm *svm)
+{
+ unsigned long dr6;
+
+ /* if we're not singlestepping, it's not ours */
+ if (!svm->nmi_singlestep)
+ return NESTED_EXIT_DONE;
+
+ /* if it's not a singlestep exception, it's not ours */
+ if (kvm_get_dr(&svm->vcpu, 6, &dr6))
+ return NESTED_EXIT_DONE;
+ if (!(dr6 & DR6_BS))
+ return NESTED_EXIT_DONE;
+
+ /* if the guest is singlestepping, it should get the vmexit */
+ if (svm->nmi_singlestep_guest_rflags & X86_EFLAGS_TF) {
+ disable_nmi_singlestep(svm);
+ return NESTED_EXIT_DONE;
+ }
+
+ /* it's ours, the nested hypervisor must not see this one */
+ return NESTED_EXIT_HOST;
+}
+
static int nested_svm_exit_special(struct vcpu_svm *svm)
{
u32 exit_code = svm->vmcb->control.exit_code;
@@ -2589,8 +2637,12 @@ static int nested_svm_intercept(struct vcpu_svm *svm)
}
case SVM_EXIT_EXCP_BASE ... SVM_EXIT_EXCP_BASE + 0x1f: {
u32 excp_bits = 1 << (exit_code - SVM_EXIT_EXCP_BASE);
- if (svm->nested.intercept_exceptions & excp_bits)
- vmexit = NESTED_EXIT_DONE;
+ if (svm->nested.intercept_exceptions & excp_bits) {
+ if (exit_code == SVM_EXIT_EXCP_BASE + DB_VECTOR)
+ vmexit = nested_svm_intercept_db(svm);
+ else
+ vmexit = NESTED_EXIT_DONE;
+ }
/* async page fault always cause vmexit */
else if ((exit_code == SVM_EXIT_EXCP_BASE + PF_VECTOR) &&
svm->apf_reason != 0)
@@ -4627,10 +4679,17 @@ static void enable_nmi_window(struct kvm_vcpu *vcpu)
== HF_NMI_MASK)
return; /* IRET will cause a vm exit */
+ if ((svm->vcpu.arch.hflags & HF_GIF_MASK) == 0)
+ return; /* STGI will cause a vm exit */
+
+ if (svm->nested.exit_required)
+ return; /* we're not going to run the guest yet */
+
/*
* Something prevents NMI from been injected. Single step over possible
* problem (IRET or exception injection or interrupt shadow)
*/
+ svm->nmi_singlestep_guest_rflags = svm_get_rflags(vcpu);
svm->nmi_singlestep = true;
svm->vmcb->save.rflags |= (X86_EFLAGS_TF | X86_EFLAGS_RF);
}
@@ -4771,6 +4830,22 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
if (unlikely(svm->nested.exit_required))
return;
+ /*
+ * Disable singlestep if we're injecting an interrupt/exception.
+ * We don't want our modified rflags to be pushed on the stack where
+ * we might not be able to easily reset them if we disabled NMI
+ * singlestep later.
+ */
+ if (svm->nmi_singlestep && svm->vmcb->control.event_inj) {
+ /*
+ * Event injection happens before external interrupts cause a
+ * vmexit and interrupts are disabled here, so smp_send_reschedule
+ * is enough to force an immediate vmexit.
+ */
+ disable_nmi_singlestep(svm);
+ smp_send_reschedule(vcpu->cpu);
+ }
+
pre_svm_run(svm);
sync_lapic_to_cr8(vcpu);
@@ -4907,6 +4982,7 @@ static void svm_vcpu_run(struct kvm_vcpu *vcpu)
mark_all_clean(svm->vmcb);
}
+STACK_FRAME_NON_STANDARD(svm_vcpu_run);
static void svm_set_cr3(struct kvm_vcpu *vcpu, unsigned long root)
{
generated by cgit v1.2.3 (git 2.39.1) at 2024-10-10 08:28:07 +0000