108 lines
3.5 KiB
Diff
108 lines
3.5 KiB
Diff
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# Commit 7dd3b06ff031c9a8c727df16c5def2afb382101c
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# Date 2013-02-28 14:00:18 +0000
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# Author Tim Deegan <tim@xen.org>
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# Committer Tim Deegan <tim@xen.org>
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vmx: fix handling of NMI VMEXIT.
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Call do_nmi() directly and explicitly re-enable NMIs rather than
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raising an NMI through the APIC. Since NMIs are disabled after the
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VMEXIT, the raised NMI would be blocked until the next IRET
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instruction (i.e. the next real interrupt, or after scheduling a PV
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guest) and in the meantime the guest will spin taking NMI VMEXITS.
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Also, handle NMIs before re-enabling interrupts, since if we handle an
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interrupt (and therefore IRET) before calling do_nmi(), we may end up
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running the NMI handler with NMIs enabled.
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Signed-off-by: Tim Deegan <tim@xen.org>
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Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
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Acked-by: Jan Beulich <jbeulich@suse.com>
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--- a/xen/arch/x86/hvm/vmx/vmx.c
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+++ b/xen/arch/x86/hvm/vmx/vmx.c
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@@ -2421,6 +2421,13 @@ void vmx_vmexit_handler(struct cpu_user_
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vector = intr_info & INTR_INFO_VECTOR_MASK;
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if ( vector == TRAP_machine_check )
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do_machine_check(regs);
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+ if ( vector == TRAP_nmi
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+ && ((intr_info & INTR_INFO_INTR_TYPE_MASK) ==
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+ (X86_EVENTTYPE_NMI << 8)) )
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+ {
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+ do_nmi(regs);
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+ enable_nmis();
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+ }
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break;
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case EXIT_REASON_MCE_DURING_VMENTRY:
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do_machine_check(regs);
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@@ -2594,7 +2601,7 @@ void vmx_vmexit_handler(struct cpu_user_
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(X86_EVENTTYPE_NMI << 8) )
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goto exit_and_crash;
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HVMTRACE_0D(NMI);
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- self_nmi(); /* Real NMI, vector 2: normal processing. */
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+ /* Already handled above. */
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break;
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case TRAP_machine_check:
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HVMTRACE_0D(MCE);
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--- a/xen/arch/x86/x86_32/entry.S
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+++ b/xen/arch/x86/x86_32/entry.S
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@@ -621,6 +621,14 @@ ENTRY(machine_check)
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pushl $TRAP_machine_check<<16
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jmp handle_nmi_mce
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+/* Enable NMIs. No special register assumptions. All registers are preserved. */
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+ENTRY(enable_nmis)
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+ /* Set up stack frame */
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+ pushf # EFLAGS
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+ push %cs # CS
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+ push $.Lret # EIP
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+ iret # Disable the hardware NMI latch
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+
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ENTRY(setup_vm86_frame)
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mov %ecx,%ds
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mov %ecx,%es
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@@ -634,7 +642,7 @@ ENTRY(setup_vm86_frame)
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.endm
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copy_vm86_words
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addl $16,%esp
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- ret
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+.Lret: ret
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.section .rodata, "a", @progbits
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--- a/xen/arch/x86/x86_64/entry.S
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+++ b/xen/arch/x86/x86_64/entry.S
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@@ -643,6 +643,22 @@ ENTRY(machine_check)
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movl $TRAP_machine_check,4(%rsp)
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jmp handle_ist_exception
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+/* Enable NMIs. No special register assumptions. Only %rax is not preserved. */
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+ENTRY(enable_nmis)
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+ movq %rsp, %rax /* Grab RSP before pushing */
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+
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+ /* Set up stack frame */
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+ pushq $0 /* SS */
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+ pushq %rax /* RSP */
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+ pushfq /* RFLAGS */
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+ pushq $__HYPERVISOR_CS /* CS */
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+ leaq 1f(%rip),%rax
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+ pushq %rax /* RIP */
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+
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+ iretq /* Disable the hardware NMI latch */
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+1:
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+ retq
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+
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.section .rodata, "a", @progbits
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ENTRY(exception_table)
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--- a/xen/include/asm-x86/processor.h
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+++ b/xen/include/asm-x86/processor.h
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@@ -584,6 +584,8 @@ DECLARE_TRAP_HANDLER(alignment_check);
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DECLARE_TRAP_HANDLER(spurious_interrupt_bug);
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#undef DECLARE_TRAP_HANDLER
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+void enable_nmis(void);
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+
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void syscall_enter(void);
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void sysenter_entry(void);
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void sysenter_eflags_saved(void);
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