From: Gerd Hoffmann <kraxel@redhat.com>
To: Laszlo Ersek <lersek@redhat.com>
Cc: pbonzini@redhat.com, qemu-devel@nongnu.org, mst@redhat.com
Subject: Re: [Qemu-devel] [PATCH 5/6] [wip] tseg, part1, not (yet) tested
Date: Wed, 22 Apr 2015 10:09:17 +0200 [thread overview]
Message-ID: <1429690157.14806.43.camel@nilsson.home.kraxel.org> (raw)
In-Reply-To: <1429628650.21164.24.camel@nilsson.home.kraxel.org>
Hi,
> tseg is just normal ram (yes, located at the end of memory), but (once
> tseg is enabled) only cpus in smm mode are allowed to access it.
> Likewise busmaster dma access is rejected, so non-smm code can't use the
> sata controller to access this indirectly.
Update: Seems tseg can be anywhere, there is a "tseg memory base"
register @ 0xac in pci config space.
Placing it at the end of memory is just what the bios is supposed to do
by default. And it makes sense to place it there.
<quote>
This register contains the base address of TSEG DRAM memory. BIOS
determines the base of TSEG memory by subtracting the TSEG size (PCI
Device 0, offset 9Eh, bits 2:1) from graphics GTT stolen base (PCI
Device 0, offset A8h, bits 31:20).
Once D_LCK has been set, these bits becomes read only.
</quote>
"GTT stolen base" equals "top of below-4g memory" for us because we
emulate the chipset variant without graphics in qemu.
cheers,
Gerd
next prev parent reply other threads:[~2015-04-22 8:09 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-04-20 9:19 [Qemu-devel] [PATCH 1/6] [fixup] add ESMRAMC default Gerd Hoffmann
2015-04-20 9:19 ` [Qemu-devel] [PATCH 2/6] add SMRAM+ESMRAMC wmask Gerd Hoffmann
2015-04-20 12:05 ` Michael S. Tsirkin
2015-04-20 9:19 ` [Qemu-devel] [PATCH 3/6] q35: implement SMRAM.D_LCK Gerd Hoffmann
2015-04-20 12:06 ` Michael S. Tsirkin
2015-04-20 9:19 ` [Qemu-devel] [PATCH 4/6] q35: add test for SMRAM.D_LCK Gerd Hoffmann
2015-04-20 12:06 ` Michael S. Tsirkin
2015-04-20 9:19 ` [Qemu-devel] [PATCH 5/6] [wip] tseg, part1, not (yet) tested Gerd Hoffmann
2015-04-20 11:45 ` Paolo Bonzini
2015-04-21 14:18 ` Laszlo Ersek
2015-04-21 15:04 ` Gerd Hoffmann
2015-04-21 15:08 ` Paolo Bonzini
2015-04-21 15:16 ` Gerd Hoffmann
2015-04-21 18:46 ` Laszlo Ersek
2015-04-22 6:07 ` Gerd Hoffmann
2015-04-22 8:09 ` Gerd Hoffmann [this message]
2015-04-22 8:52 ` Laszlo Ersek
2015-04-22 9:33 ` Gerd Hoffmann
2015-04-22 21:41 ` Laszlo Ersek
2015-04-22 21:51 ` Laszlo Ersek
2015-04-23 7:02 ` Gerd Hoffmann
2015-04-23 7:41 ` Laszlo Ersek
2015-04-23 8:33 ` Laszlo Ersek
2015-04-23 8:34 ` Gerd Hoffmann
2015-04-23 8:42 ` Laszlo Ersek
2015-04-23 10:27 ` Paolo Bonzini
2015-04-20 9:19 ` [Qemu-devel] [PATCH 6/6] [wip] tseg, part2, " Gerd Hoffmann
2015-04-21 14:30 ` Laszlo Ersek
2015-04-21 14:38 ` Paolo Bonzini
2015-04-21 15:05 ` Laszlo Ersek
2015-04-21 15:14 ` Gerd Hoffmann
2015-04-21 15:21 ` Paolo Bonzini
2015-04-21 20:31 ` [Qemu-devel] implementing EFI_SMM_CONTROL2_PROTOCOL.Trigger() (was: [PATCH 6/6] [wip] tseg, part2, not (yet) tested) Laszlo Ersek
2015-04-21 20:58 ` [Qemu-devel] implementing EFI_SMM_CONTROL2_PROTOCOL.Trigger() Paolo Bonzini
2015-04-24 11:56 ` [Qemu-devel] [edk2] implementing EFI_SMM_CONTROL2_PROTOCOL.Trigger() (was: [PATCH 6/6] [wip] tseg, part2, not (yet) tested) Yao, Jiewen
2015-04-24 13:00 ` [Qemu-devel] [edk2] implementing EFI_SMM_CONTROL2_PROTOCOL.Trigger() Paolo Bonzini
2015-04-24 13:16 ` Yao, Jiewen
2015-04-24 14:50 ` [Qemu-devel] [edk2] implementing EFI_SMM_CONTROL2_PROTOCOL.Trigger() (was: [PATCH 6/6] [wip] tseg, part2, not (yet) tested) Yao, Jiewen
2015-04-24 16:46 ` [Qemu-devel] [edk2] implementing EFI_SMM_CONTROL2_PROTOCOL.Trigger() Laszlo Ersek
2015-04-21 15:12 ` [Qemu-devel] [PATCH 6/6] [wip] tseg, part2, not (yet) tested Gerd Hoffmann
2015-04-20 12:07 ` [Qemu-devel] [PATCH 1/6] [fixup] add ESMRAMC default Michael S. Tsirkin
2015-04-20 12:27 ` Paolo Bonzini
2015-04-20 13:23 ` Gerd Hoffmann
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