Re: [PATCH 06/11] target/i386: disable/enable breakpoints on vmentry/vmexit

[Richard Henderson <richard.henderson@linaro.org>]

On 6/4/24 02:18, Paolo Bonzini wrote:
> If the required DR7 (either from the VMCB or from the host save
> area) disables a breakpoint that was enabled prior to vmentry
> or vmexit, it is left enabled and will trigger EXCP_DEBUG.
> This causes a spurious #DB on the next crossing of the breakpoint.
> 
> To disable it, vmentry/vmexit must use cpu_x86_update_dr7
> to load DR7.
> 
> Because cpu_x86_update_dr7 takes a 32-bit argument, check
> reserved bits prior to calling cpu_x86_update_dr7, and do the
> same for DR6 as well for consistency.
> 
> This scenario is tested by the "host_rflags" test in kvm-unit-tests.
> 
> Signed-off-by: Paolo Bonzini<pbonzini@redhat.com>
> ---
>   target/i386/tcg/sysemu/svm_helper.c | 25 +++++++++++++++----------
>   1 file changed, 15 insertions(+), 10 deletions(-)

Reviewed-by: Richard Henderson <richard.henderson@linaro.org>

r~