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Code Issues Releases Activity

If the guest exits due to a fault while it is executing IRET then restore

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the state of "Virtual NMI blocking" in the guest's interruptibility-state
field before resuming the guest.
This commit is contained in:
Neel Natu 2014-01-18 02:20:10 +00:00
parent bea6313e6b
commit e5a1d95089
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=260836
2 changed files with 68 additions and 4 deletions
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6
sys/amd64/vmm/intel/vmcs.h
View File

@ -330,6 +330,12 @@ vmcs_write(uint32_t encoding, uint64_t val)
#define EXIT_REASON_XSETBV 55
#define EXIT_REASON_APIC_WRITE 56
/*
* NMI unblocking due to IRET.
*
* Applies to VM-exits due to hardware exception or EPT fault.
*/
#define EXIT_QUAL_NMIUDTI (1 << 12)
/*
* VMCS interrupt information fields
*/

66
sys/amd64/vmm/intel/vmx.c
View File

@ -1155,6 +1155,37 @@ vmx_inject_interrupts(struct vmx *vmx, int vcpu, struct vlapic *vlapic)
VCPU_CTR0(vmx->vm, vcpu, "Enabling interrupt window exiting");
}
/*
* If the Virtual NMIs execution control is '1' then the logical processor
* tracks virtual-NMI blocking in the Guest Interruptibility-state field of
* the VMCS. An IRET instruction in VMX non-root operation will remove any
* virtual-NMI blocking.
*
* This unblocking occurs even if the IRET causes a fault. In this case the
* hypervisor needs to restore virtual-NMI blocking before resuming the guest.
*/
static void
vmx_restore_nmi_blocking(struct vmx *vmx, int vcpuid)
{
uint32_t gi;
VCPU_CTR0(vmx->vm, vcpuid, "Restore Virtual-NMI blocking");
gi = vmcs_read(VMCS_GUEST_INTERRUPTIBILITY);
gi |= VMCS_INTERRUPTIBILITY_NMI_BLOCKING;
vmcs_write(VMCS_GUEST_INTERRUPTIBILITY, gi);
}
static void
vmx_clear_nmi_blocking(struct vmx *vmx, int vcpuid)
{
uint32_t gi;
VCPU_CTR0(vmx->vm, vcpuid, "Clear Virtual-NMI blocking");
gi = vmcs_read(VMCS_GUEST_INTERRUPTIBILITY);
gi &= ~VMCS_INTERRUPTIBILITY_NMI_BLOCKING;
vmcs_write(VMCS_GUEST_INTERRUPTIBILITY, gi);
}
static int
vmx_emulate_cr_access(struct vmx *vmx, int vcpu, uint64_t exitqual)
{
@ -1444,7 +1475,7 @@ vmx_exit_process(struct vmx *vmx, int vcpu, struct vm_exit *vmexit)
int error, handled;
struct vmxctx *vmxctx;
struct vlapic *vlapic;
uint32_t eax, ecx, edx, gi, idtvec_info, idtvec_err, intr_info, reason;
uint32_t eax, ecx, edx, idtvec_info, idtvec_err, intr_info, reason;
uint64_t qual, gpa;
bool retu;
@ -1490,13 +1521,12 @@ vmx_exit_process(struct vmx *vmx, int vcpu, struct vm_exit *vmexit)
*/
if ((idtvec_info & VMCS_INTR_T_MASK) ==
VMCS_INTR_T_NMI) {
gi = vmcs_read(VMCS_GUEST_INTERRUPTIBILITY);
gi &= ~VMCS_INTERRUPTIBILITY_NMI_BLOCKING;
vmcs_write(VMCS_GUEST_INTERRUPTIBILITY, gi);
vmx_clear_nmi_blocking(vmx, vcpu);
}
vmcs_write(VMCS_ENTRY_INST_LENGTH, vmexit->inst_length);
}
default:
idtvec_info = 0;
break;
}
@ -1601,6 +1631,23 @@ vmx_exit_process(struct vmx *vmx, int vcpu, struct vm_exit *vmexit)
vmm_stat_incr(vmx->vm, vcpu, VMEXIT_CPUID, 1);
handled = vmx_handle_cpuid(vmx->vm, vcpu, vmxctx);
break;
case EXIT_REASON_EXCEPTION:
intr_info = vmcs_read(VMCS_EXIT_INTR_INFO);
KASSERT((intr_info & VMCS_INTR_VALID) != 0,
("VM exit interruption info invalid: %#x", intr_info));
/*
* If Virtual NMIs control is 1 and the VM-exit is due to a
* fault encountered during the execution of IRET then we must
* restore the state of "virtual-NMI blocking" before resuming
* the guest.
*
* See "Resuming Guest Software after Handling an Exception".
*/
if ((idtvec_info & VMCS_IDT_VEC_VALID) == 0 &&
(intr_info & 0xff) != IDT_DF &&
(intr_info & EXIT_QUAL_NMIUDTI) != 0)
vmx_restore_nmi_blocking(vmx, vcpu);
break;
case EXIT_REASON_EPT_FAULT:
vmm_stat_incr(vmx->vm, vcpu, VMEXIT_EPT_FAULT, 1);
/*
@ -1619,6 +1666,17 @@ vmx_exit_process(struct vmx *vmx, int vcpu, struct vm_exit *vmexit)
vmexit->u.inst_emul.gla = vmcs_gla();
vmexit->u.inst_emul.cr3 = vmcs_guest_cr3();
}
/*
* If Virtual NMIs control is 1 and the VM-exit is due to an
* EPT fault during the execution of IRET then we must restore
* the state of "virtual-NMI blocking" before resuming.
*
* See description of "NMI unblocking due to IRET" in
* "Exit Qualification for EPT Violations".
*/
if ((idtvec_info & VMCS_IDT_VEC_VALID) == 0 &&
(qual & EXIT_QUAL_NMIUDTI) != 0)
vmx_restore_nmi_blocking(vmx, vcpu);
break;
case EXIT_REASON_APIC_ACCESS:
handled = vmx_handle_apic_access(vmx, vcpu, vmexit);