Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Anthony Liguori
Paolo Bonzini pbonz...@redhat.com writes: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to zero. This will allow

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Gleb Natapov
On Mon, Jul 22, 2013 at 12:50:23PM -0500, Anthony Liguori wrote: Paolo Bonzini pbonz...@redhat.com writes: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading

[Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Orit Wasserman
Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to zero. This will allow migration from older KVM on host without unrestricted guest to hosts with restricted guest support. For

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Paolo Bonzini
Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to zero. This will allow migration from older KVM on host without

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Gleb Natapov
On Mon, Jul 22, 2013 at 11:49:25AM +0200, Paolo Bonzini wrote: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Orit Wasserman
On 07/22/2013 12:49 PM, Paolo Bonzini wrote: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to zero. This will allow

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Paolo Bonzini
Il 22/07/2013 12:10, Orit Wasserman ha scritto: As discussed offlist, I would prefer to have this in the kernel since that's where the bug is. Gleb disagrees. As this is a migration bug I prefer to fix it in the migration code only. Fixing it in the kernel will effect all scenarios that

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Andreas Färber
Am 22.07.2013 11:49, schrieb Paolo Bonzini: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to zero. This will allow

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Gleb Natapov
On Mon, Jul 22, 2013 at 12:33:31PM +0200, Andreas Färber wrote: Am 22.07.2013 11:49, schrieb Paolo Bonzini: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Juan Quintela
Orit Wasserman owass...@redhat.com wrote: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to zero. This will allow migration from older KVM on host without unrestricted

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Orit Wasserman
On 07/22/2013 01:33 PM, Andreas Färber wrote: Am 22.07.2013 11:49, schrieb Paolo Bonzini: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Juan Quintela
Orit Wasserman owass...@redhat.com wrote: On 07/22/2013 01:33 PM, Andreas Färber wrote: Am 22.07.2013 11:49, schrieb Paolo Bonzini: Il 22/07/2013 08:49, Orit Wasserman ha scritto: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Eduardo Habkost
On Mon, Jul 22, 2013 at 12:14:25PM +0200, Paolo Bonzini wrote: Il 22/07/2013 12:10, Orit Wasserman ha scritto: As discussed offlist, I would prefer to have this in the kernel since that's where the bug is. Gleb disagrees. As this is a migration bug I prefer to fix it in the migration

Re: [Qemu-devel] [PATCH 1/2] Fix real mode guest migration

2013-07-22 Thread Eric Blake
On 07/22/2013 12:49 AM, Orit Wasserman wrote: Older KVM versions save CS dpl value to an invalid value for real mode guests (0x3). This patch detect this situation when loading CPU state and set all the segments dpl to zero. This will allow migration from older KVM on host without unrestricted