Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2017-01-10 Thread Michael S. Tsirkin
On Thu, Dec 01, 2016 at 06:06:19PM +0100, Laszlo Ersek wrote: > We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could > lead to problems with backward migration: a more recent QEMU (running an > older machine type) would allow the guest, in fw_cfg_select(), to select a > high

Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-06 Thread Laszlo Ersek
On 12/06/16 13:02, Igor Mammedov wrote: > On Tue, 6 Dec 2016 12:43:06 +0100 > Laszlo Ersek wrote: > >> On 12/06/16 11:50, Igor Mammedov wrote: >>> On Thu, 1 Dec 2016 18:06:19 +0100 >>> Laszlo Ersek wrote: >>> We'd like to raise the value of

Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-06 Thread Igor Mammedov
On Tue, 6 Dec 2016 12:43:06 +0100 Laszlo Ersek wrote: > On 12/06/16 11:50, Igor Mammedov wrote: > > On Thu, 1 Dec 2016 18:06:19 +0100 > > Laszlo Ersek wrote: > > > >> We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could > >> lead to

Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-06 Thread Laszlo Ersek
On 12/06/16 11:50, Igor Mammedov wrote: > On Thu, 1 Dec 2016 18:06:19 +0100 > Laszlo Ersek wrote: > >> We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could >> lead to problems with backward migration: a more recent QEMU (running an >> older machine type)

Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-06 Thread Igor Mammedov
On Thu, 1 Dec 2016 18:06:19 +0100 Laszlo Ersek wrote: > We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could > lead to problems with backward migration: a more recent QEMU (running an > older machine type) would allow the guest, in fw_cfg_select(), to

Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-02 Thread Gerd Hoffmann
Hi, > Please check one of the links in the blurb, under which Paolo noted that > we're already above the limit in the worst (theoretical) case. Oh, ok. That changes the picture. > In practice they don't hit the limit, indeed. But creating such a case being possible (even if unlikely) is

Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-02 Thread Laszlo Ersek
On 12/02/16 12:10, Gerd Hoffmann wrote: > On Do, 2016-12-01 at 18:06 +0100, Laszlo Ersek wrote: >> We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could >> lead to problems with backward migration: a more recent QEMU (running an >> older machine type) would allow the guest, in

Re: [Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-02 Thread Gerd Hoffmann
On Do, 2016-12-01 at 18:06 +0100, Laszlo Ersek wrote: > We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could > lead to problems with backward migration: a more recent QEMU (running an > older machine type) would allow the guest, in fw_cfg_select(), to select a > high key value

[Qemu-devel] [PATCH v4 2/7] fw-cfg: turn FW_CFG_FILE_SLOTS into a device property

2016-12-01 Thread Laszlo Ersek
We'd like to raise the value of FW_CFG_FILE_SLOTS. Doing it naively could lead to problems with backward migration: a more recent QEMU (running an older machine type) would allow the guest, in fw_cfg_select(), to select a high key value that is unavailable in the same machine type implemented by