From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: Anthony PERARD <anthony.perard@citrix.com>
Cc: xen-devel@lists.xen.org
Subject: Re: OVMF very slow on AMD
Date: Wed, 27 Jul 2016 15:45:23 -0400 [thread overview]
Message-ID: <d4e581ce-7074-1e99-98ec-2d29f895af71@oracle.com> (raw)
In-Reply-To: <20160727113539.GO1835@perard.uk.xensource.com>
On 07/27/2016 07:35 AM, Anthony PERARD wrote:
> On Wed, Jul 27, 2016 at 12:08:04PM +0100, Anthony PERARD wrote:
>> I can try to describe how OVMF is setting up the memory.
> From the start of the day:
> setup gdt
> cr0 = 0x40000023
I think this is slightly odd, with bit 30 (cache disable) set. I'd
suspect that this would affect both Intel and AMD though.
Can you try clearing this bit?
-boris
>
> jump to 32bit
> cr4 = 0x640
>
> setup page tables:
> page directory attributes: (PAGE_ACCESSED + PAGE_READ_WRITE + PAGE_PRESENT)
> page tables attributes: (PAGE_2M_MBO + PAGE_ACCESSED + PAGE_DIRTY + PAGE_READ_WRITE + PAGE_PRESENT)
> I think they map the all 4GB with 2MB pages.
> set cr3.
>
> enable PAE
> set LME
> set PG
>
> jump to 64bit
>
> I think that's it, before running this painfully slow decompression
> function.
>
> Is there something wrong, or maybe missing? Is the hypervisor or maybe
> the hardware does not do the right thing?
>
> Thanks,
>
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next prev parent reply other threads:[~2016-07-27 19:45 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-14 15:53 OVMF very slow on AMD Anthony PERARD
2016-07-15 13:48 ` Konrad Rzeszutek Wilk
2016-07-15 15:22 ` Boris Ostrovsky
2016-07-27 11:08 ` Anthony PERARD
2016-07-27 11:35 ` Anthony PERARD
2016-07-27 19:45 ` Boris Ostrovsky [this message]
2016-07-28 10:18 ` Anthony PERARD
2016-07-28 10:43 ` George Dunlap
2016-07-28 10:54 ` Andrew Cooper
2016-07-28 11:28 ` Anthony PERARD
2016-07-28 15:17 ` Boris Ostrovsky
2016-07-28 15:51 ` Andrew Cooper
2016-07-28 19:25 ` Boris Ostrovsky
2016-07-28 19:44 ` Andrew Cooper
2016-07-28 19:54 ` Boris Ostrovsky
2016-07-29 15:54 ` Anthony PERARD
2016-07-18 14:10 ` Anthony PERARD
2016-07-18 15:09 ` Anthony PERARD
2016-07-22 10:40 ` Dario Faggioli
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