[PATCH 3.10 262/268] kvm: nVMX: Allow L1 to intercept software exceptions (#BP and #OF)

Willy Tarreau
2017-06-19T18:48:37Z

From: Jim Mattson <jmattson@google.com>

commit ef85b67385436ddc1998f45f1d6a210f935b3388 upstream.

When L2 exits to L0 due to "exception or NMI", software exceptions
(#BP and #OF) for which L1 has requested an intercept should be
handled by L1 rather than L0. Previously, only hardware exceptions
were forwarded to L1.

Signed-off-by: Jim Mattson <jmattson@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Willy Tarreau <w@1wt.eu>
---
arch/x86/kvm/vmx.c | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
index b4fa8a9..d9016e4 100644
--- a/arch/x86/kvm/vmx.c
+++ b/arch/x86/kvm/vmx.c
@@ -1047,10 +1047,10 @@ static inline bool nested_cpu_has_virtual_nmis(struct vmcs12 *vmcs12,
return vmcs12->pin_based_vm_exec_control & PIN_BASED_VIRTUAL_NMIS;
}

-static inline bool is_exception(u32 intr_info)
+static inline bool is_nmi(u32 intr_info)
{
return (intr_info & (INTR_INFO_INTR_TYPE_MASK | INTR_INFO_VALID_MASK))
- == (INTR_TYPE_HARD_EXCEPTION | INTR_INFO_VALID_MASK);
+ == (INTR_TYPE_NMI_INTR | INTR_INFO_VALID_MASK);
}

static void nested_vmx_vmexit(struct kvm_vcpu *vcpu);
@@ -4716,7 +4716,7 @@ static int handle_exception(struct kvm_vcpu *vcpu)
if (is_machine_check(intr_info))
return handle_machine_check(vcpu);

- if ((intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_NMI_INTR)
+ if (is_nmi(intr_info))
return 1; /* already handled by vmx_vcpu_run() */

if (is_no_device(intr_info)) {
@@ -6507,7 +6507,7 @@ static bool nested_vmx_exit_handled(struct kvm_vcpu *vcpu)

switch (exit_reason) {
case EXIT_REASON_EXCEPTION_NMI:
- if (!is_exception(intr_info))
+ if (is_nmi(intr_info))
return 0;
else if (is_page_fault(intr_info))
return enable_ept;
@@ -6803,8 +6803,7 @@ static void vmx_complete_atomic_exit(struct vcpu_vmx *vmx)
kvm_machine_check();

/* We need to handle NMIs before interrupts are enabled */
- if ((exit_intr_info & INTR_INFO_INTR_TYPE_MASK) == INTR_TYPE_NMI_INTR &&
- (exit_intr_info & INTR_INFO_VALID_MASK)) {
+ if (is_nmi(exit_intr_info)) {
kvm_before_handle_nmi(&vmx->vcpu);
asm("int $2");
kvm_after_handle_nmi(&vmx->vcpu);
--
2.8.0.rc2.1.gbe9624a