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KVM: VMX: Update instruction length on intercepted BP

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We intercept #BP while in guest debugging mode. As VM exits due to
intercepted exceptions do not necessarily come with valid
idt_vectoring, we have to update event_exit_inst_len explicitly in such
cases. At least in the absence of migration, this ensures that
re-injections of #BP will find and use the correct instruction length.

Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com>
Cc: stable@kernel.org (2.6.32, 2.6.33)
Signed-off-by: Avi Kivity <avi@redhat.com>
This commit is contained in:
Jan Kiszka 2010-02-23 17:47:53 +01:00 committed by Marcelo Tosatti
parent e54cfa97a9
commit c573cd2293
1 changed files with 13 additions and 0 deletions
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13
arch/x86/kvm/vmx.c
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@ -2775,6 +2775,12 @@ static int handle_rmode_exception(struct kvm_vcpu *vcpu,
kvm_queue_exception(vcpu, vec);
return 1;
case BP_VECTOR:
/*
* Update instruction length as we may reinject the exception
* from user space while in guest debugging mode.
*/
to_vmx(vcpu)->vcpu.arch.event_exit_inst_len =
vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
if (vcpu->guest_debug & KVM_GUESTDBG_USE_SW_BP)
return 0;
/* fall through */
@ -2897,6 +2903,13 @@ static int handle_exception(struct kvm_vcpu *vcpu)
kvm_run->debug.arch.dr7 = vmcs_readl(GUEST_DR7);
/* fall through */
case BP_VECTOR:
/*
* Update instruction length as we may reinject #BP from
* user space while in guest debugging mode. Reading it for
* #DB as well causes no harm, it is not used in that case.
*/
vmx->vcpu.arch.event_exit_inst_len =
vmcs_read32(VM_EXIT_INSTRUCTION_LEN);
kvm_run->exit_reason = KVM_EXIT_DEBUG;
kvm_run->debug.arch.pc = vmcs_readl(GUEST_CS_BASE) + rip;
kvm_run->debug.arch.exception = ex_no;