In certain scenarios, NMIs might be disabled during Xen boot process.
Such situation will cause alternative_instructions() to:
panic("Timed out waiting for alternatives self-NMI to hit");
This bug was originally seen when using tboot to boot Xen.
To prevent this from happening, enable NMIs during cpu_init().
Signed-off-by: Sergey Dyasli <[email protected]>
---
CC: Jan Beulich <[email protected]>
CC: Andrew Cooper <[email protected]>
CC: Wei Liu <[email protected]>
---
xen/arch/x86/cpu/common.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/xen/arch/x86/cpu/common.c b/xen/arch/x86/cpu/common.c
index 057859ab14..09fbd98764 100644
--- a/xen/arch/x86/cpu/common.c
+++ b/xen/arch/x86/cpu/common.c
@@ -819,6 +819,8 @@ void cpu_init(void)
#define CD(register) asm volatile ( "mov %0,%%db" #register : : "r"(0UL) );
CD(0); CD(1); CD(2); CD(3); /* no db4 and db5 */; CD(6); CD(7);
#undef CD
+
+ enable_nmis();
}
void cpu_uninit(unsigned int cpu)
--
2.17.1
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