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From: Sean Christopherson <seanjc@google.com>
To: SU Hang <darcy.sh@antgroup.com>
Cc: kvm@vger.kernel.org, pbonzini@redhat.com, thuth@redhat.com,
	drjones@redhat.com
Subject: Re: [kvm-unit-tests PATCH 2/2] x86: replace `int 0x20` with `syscall`
Date: Wed, 27 Apr 2022 01:07:08 +0000	[thread overview]
Message-ID: <YmiXPDLILqA6H79n@google.com> (raw)
In-Reply-To: <YmbFN6yKwnLDRdr8@google.com>

On Mon, Apr 25, 2022, Sean Christopherson wrote:
> On Sun, Apr 24, 2022, SU Hang wrote:
> 
> Why?  As gross as it is, I actually think INTn is a better option because it
> doesn't require writing multiple MSRs, and can work for both 64-bit and 32-bit KUT.
> The latter is currently a moot point since this code is 64-bit only, but the UMIP
> test _does_ support 32-bit, and it's do_ring3() should really be rolled into this
> framework.
> 
> Furthermore, we really should have a test to verify that KVM correctly emulates
> SYSCALL at CPL3 with EFER.SCE=0, and forcing EFER.SCE=1 just to get to CPL3 would
> make it impossible to utilize this framework for such a test.

And a concrete reason not to apply this patch: it causes the nVMX #AC test to fail:

  FAIL: #AC handled by L2
  FAIL: #AC handled by L1

  reply	other threads:[~2022-04-27  1:07 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-04-24  7:09 [kvm-unit-tests PATCH 1/2] x86: replace `push` `pop` with callee-clobbered list SU Hang
2022-04-24  7:09 ` [kvm-unit-tests PATCH 2/2] x86: replace `int 0x20` with `syscall` SU Hang
2022-04-25 15:58   ` Sean Christopherson
2022-04-27  1:07     ` Sean Christopherson [this message]
2022-04-27  9:27     ` SU Hang
2022-04-28 15:58       ` Sean Christopherson

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