From: Keir Fraser <keir@xen.org>
To: Jan Beulich <JBeulich@suse.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: xen-devel@lists.xensource.com
Subject: Re: fsincos emulation on AMD CPUs
Date: Thu, 15 Dec 2011 12:33:13 +0000 [thread overview]
Message-ID: <CB0F9989.35F66%keir@xen.org> (raw)
In-Reply-To: <CB0F9814.35F61%keir@xen.org>
On 15/12/2011 12:27, "Keir Fraser" <keir@xen.org> wrote:
> On 15/12/2011 11:15, "Jan Beulich" <JBeulich@suse.com> wrote:
>
>> +#define AMD_ERRATUM_573 \
>> + AMD_LEGACY_ERRATUM(AMD_MODEL_RANGE(0x0f, 0x0, 0x0, 0xff, 0xf), \
>> + AMD_MODEL_RANGE(0x10, 0x0, 0x0, 0xff, 0xf), \
>> + AMD_MODEL_RANGE(0x11, 0x0, 0x0, 0xff, 0xf), \
>> + AMD_MODEL_RANGE(0x12, 0x0, 0x0, 0xff, 0xf))
>> +
>> struct cpuinfo_x86;
>> int cpu_has_amd_erratum(const struct cpuinfo_x86 *, int, ...);
>>
>> Keir, what's your opinion here?
>
> Bail. :-)
More detail: the full patch is ugly and hard to test all cases. And there's
no practical scenario where we want to emulate FSINCOS on AMD -- we don't
emulate realmode on AMD, FSINCOS on a shadowed page certainly indicates that
we should unshadow the page, FSINCOS on MMIO is mad or malicious.
Pretty much the whole x87 emulation thing is for realmode on Intel.
-- Keir
> -- Keir
>
>
next prev parent reply other threads:[~2011-12-15 12:33 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-15 8:38 fsincos emulation on AMD CPUs Jan Beulich
2011-12-15 8:54 ` Paolo Bonzini
2011-12-15 10:15 ` Jan Beulich
2011-12-15 10:34 ` Paolo Bonzini
2011-12-15 11:15 ` Jan Beulich
2011-12-15 12:27 ` Keir Fraser
2011-12-15 12:33 ` Keir Fraser [this message]
2011-12-15 13:08 ` Jan Beulich
2011-12-15 13:13 ` Keir Fraser
2011-12-15 13:19 ` Jan Beulich
2011-12-15 16:52 ` Keir Fraser
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