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target-i386: defer VMEXIT to do_interrupt

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Paths through the softmmu code during code generation now need to be audited
to check for double locking of tb_lock.  In particular, VMEXIT can take tb_lock
through cpu_vmexit -> cpu_x86_update_cr4 -> tlb_flush.

To avoid this, split VMEXIT delivery in two parts, similar to what is done with
exceptions.  cpu_vmexit only records the VMEXIT exit code and information, and
cc->do_interrupt can then deliver it when it is safe to take the lock.

Reported-by: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Suggested-by: Richard Henderson <rth@twiddle.net>
Tested-by: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Richard Henderson <rth@twiddle.net>
This commit is contained in:
Paolo Bonzini 2017-03-07 12:37:36 +01:00 • committed by Alex Bennée
parent d394698d73
commit 10cde894b6
3 changed files with 26 additions and 18 deletions
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2
target/i386/cpu.h
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@ -697,6 +697,7 @@ typedef uint32_t FeatureWordArray[FEATURE_WORDS];
#define EXCP_SYSCALL 0x100 /* only happens in user only emulation
for syscall instruction */
#define EXCP_VMEXIT 0x100
/* i386-specific interrupt pending bits. */
#define CPU_INTERRUPT_POLL CPU_INTERRUPT_TGT_EXT_1
@ -1632,6 +1633,7 @@ void cpu_svm_check_intercept_param(CPUX86State *env1, uint32_t type,
uint64_t param, uintptr_t retaddr);
void cpu_vmexit(CPUX86State *nenv, uint32_t exit_code, uint64_t exit_info_1,
uintptr_t retaddr);
void do_vmexit(CPUX86State *env, uint32_t exit_code, uint64_t exit_info_1);
/* seg_helper.c */
void do_interrupt_x86_hardirq(CPUX86State *env, int intno, int is_hw);