[PATCH] Documentation: KVM: x86: Update nested live migration status on AMD

[PATCH] Documentation: KVM: x86: Update nested live migration status on AMD

[Shivansh Dhiman]

The "Live migration with nested KVM" section is stale for AMD systems
and needs an update.  Migrating an SVM L1 guest with a live L2 guest in
it works, and has been tested with Linux 7.2 and QEMU 11.1.0.  So,
replace the AMD-specific caveats accordingly.

Signed-off-by: Shivansh Dhiman <shivansh.dhiman@amd.com>
---
 .../virt/kvm/x86/running-nested-guests.rst       | 16 +++-------------
 1 file changed, 3 insertions(+), 13 deletions(-)

diff --git a/Documentation/virt/kvm/x86/running-nested-guests.rst b/Documentation/virt/kvm/x86/running-nested-guests.rst
index 87326413d5c7..e41a50816058 100644
--- a/Documentation/virt/kvm/x86/running-nested-guests.rst
+++ b/Documentation/virt/kvm/x86/running-nested-guests.rst
@@ -186,21 +186,11 @@ Live migration with nested KVM
 
 Migrating an L1 guest, with a  *live* nested guest in it, to another
 bare metal host, works as of Linux kernel 5.3 and QEMU 4.2.0 for
-Intel x86 systems, and even on older versions for s390x.
-
-On AMD systems, once an L1 guest has started an L2 guest, the L1 guest
-should no longer be migrated or saved (refer to QEMU documentation on
-"savevm"/"loadvm") until the L2 guest shuts down.  Attempting to migrate
-or save-and-load an L1 guest while an L2 guest is running will result in
-undefined behavior.  You might see a ``kernel BUG!`` entry in ``dmesg``, a
-kernel 'oops', or an outright kernel panic.  Such a migrated or loaded L1
-guest can no longer be considered stable or secure, and must be restarted.
-Migrating an L1 guest merely configured to support nesting, while not
-actually running L2 guests, is expected to function normally even on AMD
-systems but may fail once guests are started.
+Intel x86 systems, and even on older versions for s390x.  On AMD x86
+systems, it works with Linux kernel 7.2 and QEMU 11.1.0, or later.
 
 Migrating an L2 guest is always expected to succeed, so all the following
-scenarios should work even on AMD systems:
+scenarios should work:
 
 - Migrating a nested guest (L2) to another L1 guest on the *same* bare
   metal host.

base-commit: 6bd2905303c58679e303941b7d8ae8c074cd95ce
-- 
2.43.0

Re: [PATCH] Documentation: KVM: x86: Update nested live migration status on AMD

[Sean Christopherson]

On Thu, 08 Oct 2026 09:59:35 +0000, Shivansh Dhiman wrote:
> The "Live migration with nested KVM" section is stale for AMD systems
> and needs an update.  Migrating an SVM L1 guest with a live L2 guest in
> it works, and has been tested with Linux 7.2 and QEMU 11.1.0.  So,
> replace the AMD-specific caveats accordingly.

Applied to kvm-x86 misc, thanks!

[1/1] Documentation: KVM: x86: Update nested live migration status on AMD
      https://github.com/kvm-x86/linux/commit/a9dfce9b3fae

--
https://github.com/kvm-x86/linux/tree/next

Re: [PATCH] Documentation: KVM: x86: Update nested live migration status on AMD

[Shivansh Dhiman]

On 13-11-26 19:17, Sean Christopherson wrote:
> On Thu, 08 Oct 2026 09:59:35 +0000, Shivansh Dhiman wrote:
>> The "Live migration with nested KVM" section is stale for AMD systems
>> and needs an update.  Migrating an SVM L1 guest with a live L2 guest in
>> it works, and has been tested with Linux 7.2 and QEMU 11.1.0.  So,
>> replace the AMD-specific caveats accordingly.
> 
> Applied to kvm-x86 misc, thanks!

Thank you for picking up the nSVM documentation update.

> 
> [1/1] Documentation: KVM: x86: Update nested live migration status on AMD
>       https://github.com/kvm-x86/linux/commit/a9dfce9b3fae
> 
> --
> https://github.com/kvm-x86/linux/tree/next