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| author | Jan Beulich <jbeulich@suse.com> | 2013-03-04 10:19:34 +0100 |
|---|---|---|
| committer | Jan Beulich <jbeulich@suse.com> | 2013-03-04 10:19:34 +0100 |
| commit | d463b005bbd6475ed930a302821efe239e1b2cf9 (patch) | |
| tree | 32515ad83274734890878d6f995b288c35b26efd /xen/arch/x86/x86_64 | |
| parent | e6a6fd63652814e5c36a0016c082032f798ced1f (diff) | |
| download | xen-d463b005bbd6475ed930a302821efe239e1b2cf9.tar.gz xen-d463b005bbd6475ed930a302821efe239e1b2cf9.tar.bz2 xen-d463b005bbd6475ed930a302821efe239e1b2cf9.zip | |
x86: defer processing events on the NMI exit path
Otherwise, we may end up in the scheduler, keeping NMIs masked for a
possibly unbounded period of time (until whenever the next IRET gets
executed). Enforce timely event processing by sending a self IPI.
Of course it's open for discussion whether to always use the straight
exit path from handle_ist_exception.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Keir Fraser <keir@xen.org>
Diffstat (limited to 'xen/arch/x86/x86_64')
| -rw-r--r-- | xen/arch/x86/x86_64/compat/entry.S | 2 | ||||
| -rw-r--r-- | xen/arch/x86/x86_64/entry.S | 27 |
2 files changed, 23 insertions, 6 deletions
diff --git a/xen/arch/x86/x86_64/compat/entry.S b/xen/arch/x86/x86_64/compat/entry.S index 7051f90213..7769019e27 100644 --- a/xen/arch/x86/x86_64/compat/entry.S +++ b/xen/arch/x86/x86_64/compat/entry.S @@ -171,7 +171,7 @@ compat_bad_hypercall: jmp compat_test_all_events /* %rbx: struct vcpu, interrupts disabled */ -compat_restore_all_guest: +ENTRY(compat_restore_all_guest) ASSERT_INTERRUPTS_DISABLED RESTORE_ALL adj=8 compat=1 .Lft0: iretq diff --git a/xen/arch/x86/x86_64/entry.S b/xen/arch/x86/x86_64/entry.S index 408c348696..82d9881945 100644 --- a/xen/arch/x86/x86_64/entry.S +++ b/xen/arch/x86/x86_64/entry.S @@ -11,6 +11,7 @@ #include <asm/apicdef.h> #include <asm/page.h> #include <public/xen.h> +#include <irq_vectors.h> ALIGN /* %rbx: struct vcpu */ @@ -615,6 +616,9 @@ ENTRY(early_page_fault) jmp restore_all_xen .popsection +ENTRY(nmi) + pushq $0 + movl $TRAP_nmi,4(%rsp) handle_ist_exception: SAVE_ALL testb $3,UREGS_cs(%rsp) @@ -629,12 +633,25 @@ handle_ist_exception: movzbl UREGS_entry_vector(%rsp),%eax leaq exception_table(%rip),%rdx callq *(%rdx,%rax,8) - jmp ret_from_intr + cmpb $TRAP_nmi,UREGS_entry_vector(%rsp) + jne ret_from_intr -ENTRY(nmi) - pushq $0 - movl $TRAP_nmi,4(%rsp) - jmp handle_ist_exception + /* We want to get straight to the IRET on the NMI exit path. */ + testb $3,UREGS_cs(%rsp) + jz restore_all_xen + GET_CURRENT(%rbx) + /* Send an IPI to ourselves to cover for the lack of event checking. */ + movl VCPU_processor(%rbx),%eax + shll $IRQSTAT_shift,%eax + leaq irq_stat(%rip),%rcx + cmpl $0,(%rcx,%rax,1) + je 1f + movl $EVENT_CHECK_VECTOR,%edi + call send_IPI_self +1: movq VCPU_domain(%rbx),%rax + cmpb $0,DOMAIN_is_32bit_pv(%rax) + je restore_all_guest + jmp compat_restore_all_guest ENTRY(nmi_crash) pushq $0 |