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From: "Jan Beulich" <JBeulich@suse.com>
To: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Xen-devel <xen-devel@lists.xen.org>
Subject: Re: [PATCH 7/7] x86/asm: Clobber %r{8..15} on exit to 32bit PV guests
Date: Wed, 03 May 2017 03:13:48 -0600	[thread overview]
Message-ID: <5909BB6C02000078001563AA@prv-mh.provo.novell.com> (raw)
In-Reply-To: <1493748326-9582-8-git-send-email-andrew.cooper3@citrix.com>

>>> On 02.05.17 at 20:05, <andrew.cooper3@citrix.com> wrote:
> @@ -366,6 +367,16 @@ static always_inline void stac(void)
>          LOAD_ONE_REG(bp, \compat)
>          LOAD_ONE_REG(bx, \compat)
>          subq  $-(UREGS_error_code-UREGS_r15+\adj), %rsp
> +.if \compat
> +        xor %r8d, %r8d
> +        xor %r9d, %r9d
> +        xor %r10d, %r10d
> +        xor %r11d, %r11d
> +        xor %r12d, %r12d
> +        xor %r13d, %r13d
> +        xor %r14d, %r14d
> +        xor %r15d, %r15d
> +.endif
>  .endm

Rather than having yet another .if, I think this would better be the
.else to one of the existing ones. Possibly even two .else-s, one
each for the R8-R11 and R12-R15 register ranges.

Also the d suffixes on the register names are pretty pointless here,
as a REX prefix is going to be needed anyway.

Jan


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  reply	other threads:[~2017-05-03  9:13 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-05-02 18:05 [PATCH 0/7] XSAs 213-315 followups Andrew Cooper
2017-05-02 18:05 ` [PATCH 1/7] x86/traps: Drop 32bit fields out of tss_struct Andrew Cooper
2017-05-03  8:10   ` Jan Beulich
2017-05-03 12:33     ` Andrew Cooper
2017-05-03  9:48   ` Wei Liu
2017-05-02 18:05 ` [PATCH 2/7] x86/traps: Poison unused stack pointers in the TSS Andrew Cooper
2017-05-03  8:14   ` Jan Beulich
2017-05-03 12:47     ` Andrew Cooper
2017-05-03 13:29   ` [PATCH v2 " Andrew Cooper
2017-05-03 13:45     ` Jan Beulich
2017-05-02 18:05 ` [PATCH 3/7] x86/mm: Further restrict permissions on some virtual mappings Andrew Cooper
2017-05-03  8:49   ` Jan Beulich
2017-05-03 13:38     ` Andrew Cooper
2017-05-03 13:48       ` Jan Beulich
2017-05-03  9:48   ` Wei Liu
2017-05-03 10:11   ` Tim Deegan
2017-05-03 11:13   ` George Dunlap
2017-05-02 18:05 ` [PATCH 4/7] x86/traps: Rename compat_hypercall() to entry_int82() Andrew Cooper
2017-05-03  8:55   ` Jan Beulich
2017-05-03 13:41     ` Andrew Cooper
2017-05-02 18:05 ` [PATCH 5/7] x86/traps: Lift all non-entrypoint logic in entry_int82() up into C Andrew Cooper
2017-05-03  9:02   ` Jan Beulich
2017-05-03 11:26     ` Wei Liu
2017-05-03 11:38       ` Andrew Cooper
2017-05-03 11:43         ` Wei Liu
2017-05-03 12:02         ` Jan Beulich
2017-05-03 12:18           ` Andrew Cooper
2017-05-03 12:37             ` Jan Beulich
2017-05-03 18:29               ` Andrew Cooper
2017-05-04  7:27                 ` Jan Beulich
2017-05-04  9:27                   ` Andrew Cooper
2017-05-04  9:36                     ` Jan Beulich
2017-05-04  9:57                       ` Andrew Cooper
2017-05-03 12:00       ` Jan Beulich
2017-05-04 10:01     ` [PATCH v2 " Andrew Cooper
2017-05-04 10:16       ` Andrew Cooper
2017-05-04 10:28         ` Jan Beulich
2017-05-04 11:09           ` Andrew Cooper
2017-05-04 10:22       ` Jan Beulich
2017-05-02 18:05 ` [PATCH 6/7] x86/asm: Fold LOAD_C_CLOBBERED into RESTORE_ALL Andrew Cooper
2017-05-03  9:08   ` Jan Beulich
2017-05-03  9:48   ` Wei Liu
2017-05-02 18:05 ` [PATCH 7/7] x86/asm: Clobber %r{8..15} on exit to 32bit PV guests Andrew Cooper
2017-05-03  9:13   ` Jan Beulich [this message]
2017-05-03 17:51     ` [PATCH v2 " Andrew Cooper
2017-05-04  8:50       ` Jan Beulich
2017-05-04 11:11 ` [RFC for 4.9] [PATCH 0/7] XSAs 213-315 followups Andrew Cooper
2017-05-04 12:52   ` Julien Grall

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