| Date | Thu, 22 Apr 2010 12:08:28 -0700 | From | Greg KH <> | Subject | [057/197] KVM: VMX: Update instruction length on intercepted BP |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Jan Kiszka <jan.kiszka@siemens.com>
commit c573cd22939e54fc1b8e672054a505048987a7cb upstream
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> Signed-off-by: Avi Kivity <avi@redhat.com> Signed-off-by: Stefan Bader <stefan.bader@canonical.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> --- arch/x86/kvm/vmx.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)
--- a/arch/x86/kvm/vmx.c +++ b/arch/x86/kvm/vmx.c @@ -2674,6 +2674,12 @@ static int handle_rmode_exception(struct 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 */ @@ -2790,6 +2796,13 @@ static int handle_exception(struct kvm_v 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;
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