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Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation I
From: |
Michael S. Tsirkin |
Subject: |
Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support |
Date: |
Tue, 7 Feb 2017 18:22:01 +0200 |
On Tue, Feb 07, 2017 at 05:04:56PM +0100, Igor Mammedov wrote:
> On Tue, 7 Feb 2017 17:35:19 +0200
> "Michael S. Tsirkin" <address@hidden> wrote:
>
> > On Tue, Feb 07, 2017 at 03:00:32PM +0100, Igor Mammedov wrote:
> > > On Mon, 6 Feb 2017 19:41:36 +0200
> > > "Michael S. Tsirkin" <address@hidden> wrote:
> > >
> > > > On Mon, Feb 06, 2017 at 09:29:30AM -0800, Ben Warren wrote:
> > > > >
> > > > > On Feb 6, 2017, at 8:15 AM, Michael S. Tsirkin <address@hidden>
> > > > > wrote:
> > > > >
> > > > > On Sun, Feb 05, 2017 at 01:12:00AM -0800, address@hidden wrote:
> > > > >
> > > > > From: Ben Warren <address@hidden>
> > > > >
> > > > > This implements the VM Generation ID feature by passing a
> > > > > 128-bit
> > > > > GUID to the guest via a fw_cfg blob.
> > > > > Any time the GUID changes, an ACPI notify event is sent to
> > > > > the guest
> > > > >
> > > > > The user interface is a simple device with one parameter:
> > > > > - guid (string, must be "auto" or in UUID format
> > > > > xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx)
> > > > >
> > > > > Signed-off-by: Ben Warren <address@hidden>
> > > > >
> > > [...]
> > >
> > > > >
> > > > > This variable name was suggested by Laszlo. the ‘a’ in ‘vgia’ refers
> > > > > to
> > > > > address, but I’ll add some comments.
> > > >
> > > > vmgenid_addr_le?
> > > >
> > > >
> > > > > How about we make it 8 byte so it's future proof?
> > > > >
> > > > > I can do that, but a previous conversation we had made it clear that
> > > > > guests
> > > > > would never allocate above 4GB so 64 bits wasn’t necessary.
> > > >
> > > > Right, it's just very painful to change once we make it 32 bit.
> > > I'd keep it 32 bit since it's in variable in global AML context and our
> > > table revision is 1, so per spec OSPM should handle it as 32 number.
> > > Chances of guest survival on boot would depend on AML interpreter
> > > tolerance
> > > to AML errors, which for windows usually is 0 and leads to non obvious
> > > BSOD.
> > > If we leave DWORD, even XP will be able to boot fine and only report
> > > unknown device.
> >
> > AML reports 2 DWORDS per spec, no issue there. I guess it's exactly for
> > XP compatibility.
>
> it's only ADDR method thought but we are talking about
> Named DWORD vs QWORD VGIA variable which is patched by linker command
Oh sorry. Yes, you want to keep that one a DWORD. Does not affect
the interface. So write 64 bits into fw cfg, but patch 32 bits
into AML.
--
MST
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, (continued)
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Ben Warren, 2017/02/06
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Michael S. Tsirkin, 2017/02/06
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Ben Warren, 2017/02/06
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Michael S. Tsirkin, 2017/02/06
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Ben Warren, 2017/02/06
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Michael S. Tsirkin, 2017/02/06
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Ben Warren, 2017/02/06
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Igor Mammedov, 2017/02/07
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Michael S. Tsirkin, 2017/02/07
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Igor Mammedov, 2017/02/07
- Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support,
Michael S. Tsirkin <=
Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Igor Mammedov, 2017/02/07
Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Laszlo Ersek, 2017/02/07
Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Ben Warren, 2017/02/08
Re: [Qemu-devel] [PATCH v5 05/10] ACPI: Add Virtual Machine Generation ID support, Laszlo Ersek, 2017/02/08