Messages in this thread | ![/](/images/icornerl.gif) | | From | Vitaly Kuznetsov <> | Subject | Re: [PATCH] selftests: kvm: fix sync_regs_test with newer gccs | Date | Wed, 09 Oct 2019 14:29:45 +0200 |
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Paolo Bonzini <pbonzini@redhat.com> writes:
> On 09/10/19 12:42, Vitaly Kuznetsov wrote: >> Paolo Bonzini <pbonzini@redhat.com> writes: >>> There is no practical difference with Vitaly's patch. The first >>> _vcpu_run has no pre-/post-conditions on the value of %rbx: >> >> I think what Sean was suggesting is to prevent GCC from inserting >> anything (and thus clobbering RBX) between the call to guest_call() and >> the beginning of 'asm volatile' block by calling *inside* 'asm volatile' >> block instead. > > Yes, but there is no way that clobbering RBX will break the test, > because RBX is not initialized until after the first _vcpu_run succeeds. >
Right, we're always resuming after so potential clobbering doesn't matter. Thanks!
-- Vitaly
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