From: Paolo Bonzini <pbonzini@redhat.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: qemu-devel@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 1/2] q35: implement SMRAM.D_LCK
Date: Thu, 16 Apr 2015 10:12:12 +0200 [thread overview]
Message-ID: <552F6EDC.4040900@redhat.com> (raw)
In-Reply-To: <1429106337.6219.5.camel@nilsson.home.kraxel.org>
On 15/04/2015 15:58, Gerd Hoffmann wrote:
> The "A Tour Beyond BIOS Implementing S3 Resume with EDKII" white paper
> lists "Lock SMM. This must be done to maintain SMM integrity." as todo
> list item for the edk2 resume code path (page 18).
>
> So it seems to me it is the job of the firmware to re-lock smm after S3
> (and before handing control back to the OS, obviously).
Right, however "D_LCK can be set to 1 via a normal configuration space
write but can only be cleared by a Full Reset." A Full Reset is the
PLTRST# pin, which is asserted by the south bridge during power-up and
during CF9h reset. S3 doesn't seem to be included.
My reading of the EDK2 whitepaper is that this may vary for other chipsets.
Paolo
next prev parent reply other threads:[~2015-04-16 8:12 UTC|newest]
Thread overview: 10+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-14 13:12 [Qemu-devel] [PATCH 1/2] q35: implement SMRAM.D_LCK Gerd Hoffmann
2015-04-14 13:12 ` [Qemu-devel] [PATCH 2/2] q35: add test for SMRAM.D_LCK Gerd Hoffmann
2015-04-14 14:35 ` [Qemu-devel] [PATCH 1/2] q35: implement SMRAM.D_LCK Paolo Bonzini
2015-04-15 13:58 ` Gerd Hoffmann
2015-04-16 8:12 ` Paolo Bonzini [this message]
2015-04-18 21:08 ` Laszlo Ersek
2015-04-14 15:41 ` Michael S. Tsirkin
2015-04-14 15:51 ` Michael S. Tsirkin
2015-04-15 14:12 ` Gerd Hoffmann
2015-04-16 8:05 ` Michael S. Tsirkin
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