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From: Max Reitz <mreitz@redhat.com>
To: Sam Eiderman <shmuel.eiderman@oracle.com>,
	kwolf@redhat.com, qemu-block@nongnu.org, qemu-devel@nongnu.org,
	seabios@seabios.org, kraxel@redhat.com, kevin@koconnor.net
Cc: liran.alon@oracle.com, karl.heubaum@oracle.com, arbel.moshe@oracle.com
Subject: Re: [Qemu-devel] [QEMU] [PATCH v5 0/8] Add Qemu to SeaBIOS LCHS interface
Date: Tue, 13 Aug 2019 21:35:06 +0200	[thread overview]
Message-ID: <3f9009fc-b478-60e1-dbcd-7782336c26e7@redhat.com> (raw)
In-Reply-To: <20190626123948.10199-1-shmuel.eiderman@oracle.com>


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On 26.06.19 14:39, Sam Eiderman wrote:
> v1:
> 
> Non-standard logical geometries break under QEMU.
> 
> A virtual disk which contains an operating system which depends on
> logical geometries (consistent values being reported from BIOS INT13
> AH=08) will most likely break under QEMU/SeaBIOS if it has non-standard
> logical geometries - for example 56 SPT (sectors per track).
> No matter what QEMU will guess - SeaBIOS, for large enough disks - will
> use LBA translation, which will report 63 SPT instead.
> 
> In addition we can not enforce SeaBIOS to rely on phyiscal geometries at
> all. A virtio-blk-pci virtual disk with 255 phyiscal heads can not
> report more than 16 physical heads when moved to an IDE controller, the
> ATA spec allows a maximum of 16 heads - this is an artifact of
> virtualization.
> 
> By supplying the logical geometies directly we are able to support such
> "exotic" disks.
> 
> We will use fw_cfg to do just that.

(From a block perspective,) I didn’t find anything too bad, so:

Acked-by: Max Reitz <mreitz@redhat.com>


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      parent reply	other threads:[~2019-08-13 19:35 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-26 12:39 [Qemu-devel] [QEMU] [PATCH v5 0/8] Add Qemu to SeaBIOS LCHS interface Sam Eiderman
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 1/8] block: Refactor macros - fix tabbing Sam Eiderman
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 2/8] block: Support providing LCHS from user Sam Eiderman
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 3/8] bootdevice: Add interface to gather LCHS Sam Eiderman
2019-08-13 18:51   ` Max Reitz
2019-08-22 15:13     ` Sam Eiderman via Qemu-devel
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 4/8] scsi: Propagate unrealize() callback to scsi-hd Sam Eiderman
2019-08-13 19:06   ` Max Reitz
2019-08-25 13:35     ` Sam Eiderman via Qemu-devel
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 5/8] bootdevice: Gather LCHS from all relevant devices Sam Eiderman
2019-08-13 19:05   ` Max Reitz
2019-08-25 13:38     ` Sam Eiderman via Qemu-devel
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 6/8] bootdevice: Refactor get_boot_devices_list Sam Eiderman
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 7/8] bootdevice: FW_CFG interface for LCHS values Sam Eiderman
2019-06-26 12:39 ` [Qemu-devel] [QEMU] [PATCH v5 8/8] hd-geo-test: Add tests for lchs override Sam Eiderman
2019-07-01  7:41 ` [Qemu-devel] [QEMU] [PATCH v5 0/8] Add Qemu to SeaBIOS LCHS interface Gerd Hoffmann
2019-07-08 17:30   ` Sam Eiderman
2019-07-17 19:03     ` Sam Eiderman
2019-07-17 19:46       ` Kevin Wolf
2019-07-19 10:10         ` Sam Eiderman
2019-07-25  0:47           ` [Qemu-devel] [Qemu-block] " John Snow
2019-07-25  0:50             ` John Snow
2019-07-25 19:42               ` Laszlo Ersek
2019-07-30 11:35               ` Gerd Hoffmann
2019-08-13 19:35 ` Max Reitz [this message]

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