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Re: [Qemu-devel] [PATCH v3 09/11] target-i386: defer VMEXIT to do_interr

From: Richard Henderson
Subject: Re: [Qemu-devel] [PATCH v3 09/11] target-i386: defer VMEXIT to do_interrupt
Date: Wed, 8 Mar 2017 06:23:58 +1100
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.7.0

On 03/08/2017 02:50 AM, Alex Bennée wrote:
From: Paolo Bonzini <address@hidden>

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 <address@hidden>
Suggested-by: Richard Henderson <address@hidden>
Tested-by: Alexander Boettcher <address@hidden>
Signed-off-by: Paolo Bonzini <address@hidden>
Signed-off-by: Alex Bennée <address@hidden>
 target/i386/cpu.h        |  2 ++
 target/i386/seg_helper.c | 20 +++++++++++---------
 target/i386/svm_helper.c | 22 +++++++++++++---------
 3 files changed, 26 insertions(+), 18 deletions(-)

Reviewed-by: Richard Henderson <address@hidden>


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