From: Keir Fraser <keir.xen@gmail.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>,
Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>,
Boris Ostrovsky <boris.ostrovsky@oracle.com>,
Jacob Shin <jacob.shin@amd.com>,
suravee.suthikulpanit@amd.com
Subject: Re: [PATCH 4/4] SVM: streamline entry.S code
Date: Mon, 26 Aug 2013 18:20:20 +0100 [thread overview]
Message-ID: <CE414CE4.5B85E%keir.xen@gmail.com> (raw)
In-Reply-To: <521B8037.3090809@citrix.com>
On 26/08/2013 17:20, "Andrew Cooper" <andrew.cooper3@citrix.com> wrote:
> Having read the manual several times, I am now more and more confused about
> this.
>
> My reading of the AMD programmer manual vol 3 indicates that %rax after VMRUN
> completes will be the host %rax, i.e. VCPU_svm_vmcb_pa.
Yes.
> However, I cant find anywhere in the code which overwrites regs->rax from
> vmcb->rax, which I would have thought would have thought would cause utter
> devastation in combination with the generic functions working with a
> cpu_user_regs structure.
It's right there in entry.S: 'mov VMCB_rax(%rcx),%rax; mov
%rax,UREGS_rax(%rsp)'
> The alternative is that %rax after VMRUN is actually the guest %rax, at which
> point the pushes used to do the correct thing, but are now broken by this
> patch clobbering it before being saved.
>
> Can someone with more knowledge please confirm? I really hope I have
> overlooked something in the code.
:)
-- Keir
next prev parent reply other threads:[~2013-08-26 17:20 UTC|newest]
Thread overview: 60+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-08-23 13:58 [PATCH 0/4] HVM: produce better binary code Jan Beulich
2013-08-23 14:01 ` [PATCH 1/4] VMX: streamline entry.S code Jan Beulich
2013-08-26 10:44 ` Andrew Cooper
2013-08-26 11:01 ` Jan Beulich
2013-08-26 11:48 ` Andrew Cooper
2013-08-26 13:12 ` Jan Beulich
2013-08-26 13:22 ` Andrew Cooper
2013-08-29 11:01 ` Tim Deegan
2013-08-29 12:35 ` Jan Beulich
2013-08-23 14:02 ` [PATCH 2/4] VMX: move various uses of UD2 out of fast paths Jan Beulich
2013-08-23 22:06 ` Andrew Cooper
2013-08-26 8:50 ` Jan Beulich
2013-08-26 9:07 ` Andrew Cooper
2013-08-26 8:58 ` [PATCH v2 " Jan Beulich
2013-08-26 9:09 ` Andrew Cooper
2013-08-29 11:08 ` Tim Deegan
2013-08-23 14:03 ` [PATCH 3/4] VMX: use proper instruction mnemonics if assembler supports them Jan Beulich
2013-08-24 22:18 ` Andrew Cooper
2013-08-26 9:06 ` Jan Beulich
2013-08-26 9:25 ` Andrew Cooper
2013-08-26 9:41 ` Jan Beulich
2013-08-26 10:18 ` [PATCH v3 " Jan Beulich
2013-08-26 13:05 ` Andrew Cooper
2013-08-26 13:20 ` Jan Beulich
2013-08-26 14:03 ` [PATCH v4 " Jan Beulich
2013-08-26 14:18 ` Andrew Cooper
2013-08-26 14:29 ` Jan Beulich
2013-08-26 15:07 ` Andrew Cooper
2013-08-26 15:10 ` Andrew Cooper
2013-08-26 15:30 ` Jan Beulich
2013-08-26 15:29 ` Jan Beulich
2013-08-26 15:33 ` Andrew Cooper
2013-08-26 15:31 ` [PATCH v5 " Jan Beulich
2013-08-26 15:36 ` Andrew Cooper
2013-08-29 11:47 ` Tim Deegan
2013-08-29 12:30 ` Jan Beulich
2013-08-29 13:11 ` Tim Deegan
2013-08-29 13:27 ` Jan Beulich
2013-08-29 14:02 ` Tim Deegan
2013-08-29 12:45 ` Jan Beulich
2013-08-29 13:19 ` Tim Deegan
2013-08-26 9:03 ` [PATCH v2 " Jan Beulich
2013-08-23 14:04 ` [PATCH 4/4] SVM: streamline entry.S code Jan Beulich
2013-08-26 16:20 ` Andrew Cooper
2013-08-26 17:20 ` Keir Fraser [this message]
2013-08-26 17:46 ` Andrew Cooper
2013-08-26 21:47 ` Andrew Cooper
2013-08-27 7:38 ` Jan Beulich
2013-08-29 11:56 ` Tim Deegan
2013-09-04 14:39 ` Boris Ostrovsky
2013-09-04 14:50 ` Jan Beulich
2013-09-04 15:09 ` Boris Ostrovsky
2013-09-04 15:20 ` Jan Beulich
2013-09-04 16:42 ` Boris Ostrovsky
2013-09-05 7:10 ` Jan Beulich
2013-09-04 10:06 ` Ping: [PATCH 0/4] HVM: produce better binary code Jan Beulich
2013-09-04 16:16 ` Andrew Cooper
2013-09-04 16:30 ` Tim Deegan
2013-09-05 7:52 ` Jan Beulich
2013-09-05 7:58 ` Tim Deegan
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