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From: "Gerd Hoffmann" <kraxel@redhat.com>
To: devel@edk2.groups.io, pedro.falcato@gmail.com
Cc: "Ard Biesheuvel" <ardb+tianocore@kernel.org>,
	"László Érsek" <lersek@redhat.com>,
	"Jordan Justen" <jordan.l.justen@intel.com>,
	"Pawel Polawski" <ppolawsk@redhat.com>,
	"Oliver Steffen" <osteffen@redhat.com>,
	"Jiewen Yao" <jiewen.yao@intel.com>
Subject: Re: [edk2-devel] [PATCH 2/2] OvmfPkg/PlatformInitLib: check 64bit mmio window for resource conflicts
Date: Mon, 9 Jan 2023 08:02:44 +0100	[thread overview]
Message-ID: <20230109070244.txlzhnazphkl5unl@sirius.home.kraxel.org> (raw)
In-Reply-To: <CAKbZUD0RfG_LeSHwmFHLAn_=k+9RjBezPKZiFUhfHbb--fQi-Q@mail.gmail.com>

On Fri, Jan 06, 2023 at 08:39:38PM +0000, Pedro Falcato wrote:
> On Fri, Jan 6, 2023 at 2:04 PM Gerd Hoffmann <kraxel@redhat.com> wrote:
> 
> > Add new operation mode to PlatformScanOrAdd64BitE820Ram() which checks
> > whenever any reservations from the qemu e820 table overlap with the mmio
> > window.  Should that be the case move it to avoid the conflict.
> >
> Hi,
> 
> In what case could this happen? Does QEMU ever place e820 entries inside
> the PCI MMIO window? Why?

Well, the *firmware* picks where it places the PCI MMIO window.  So it's
not qemu creating a conflict ;)

> (In fact, when does QEMU even add a reservation in the e820? I've never
> seen one.)

New enough qemu adds a reservation just below 1TB when running on AMD
processors (or emulating one with tcg).  That window is used by the
iommu.

take care,
  Gerd


  reply	other threads:[~2023-01-09  7:02 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-06 14:04 [PATCH 0/2] OvmfPkg: check 64bit mmio window for resource conflicts Gerd Hoffmann
2023-01-06 14:04 ` [PATCH 1/2] OvmfPkg/PlatformInitLib: update PlatformScanOrAdd64BitE820Ram documentation Gerd Hoffmann
2023-01-09  8:07   ` [edk2-devel] " Laszlo Ersek
2023-01-09 10:15     ` Gerd Hoffmann
2023-01-09 11:30       ` Laszlo Ersek
2023-01-06 14:04 ` [PATCH 2/2] OvmfPkg/PlatformInitLib: check 64bit mmio window for resource conflicts Gerd Hoffmann
2023-01-06 20:39   ` [edk2-devel] " Pedro Falcato
2023-01-09  7:02     ` Gerd Hoffmann [this message]
2023-01-06 14:14 ` [PATCH 0/2] OvmfPkg: " Ard Biesheuvel
2023-01-06 15:32   ` Gerd Hoffmann
2023-01-06 15:39     ` Yao, Jiewen

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