From: Sean Christopherson <seanjc@google.com>
To: SU Hang <darcy.sh@antgroup.com>
Cc: drjones@redhat.com, kvm@vger.kernel.org, pbonzini@redhat.com,
thuth@redhat.com
Subject: Re: [kvm-unit-tests PATCH 2/2] x86: replace `int 0x20` with `syscall`
Date: Thu, 28 Apr 2022 15:58:06 +0000 [thread overview]
Message-ID: <Ymq5jsuPIjkXSQxj@google.com> (raw)
In-Reply-To: <20220427092700.98464-1-darcy.sh@antgroup.com>
On Wed, Apr 27, 2022, SU Hang wrote:
> > It doesn't matter at this time because this framework doesn't ses SYSRET, but
> > this should be USER_CS or USER_CS64.
> Oops, intel SDM vol.3 <chap 5.8.8> says:
> """
> When SYSRET transfers control to 64-bit mode user code using REX.W, the
> processor gets the privilege level 3 target code segment, instruction pointer,
> stack segment, and flags as follows:
> • Target code segment — Reads a non-NULL selector from IA32_STAR[63:48] + 16.
Ugh, missed that detail.
> • Stack segment — IA32_STAR[63:48] + 8.
> """
prev parent reply other threads:[~2022-04-28 15:58 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
2022-04-27 9:27 ` SU Hang
2022-04-28 15:58 ` Sean Christopherson [this message]
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