On Wed, Jan 28, 2026 at 05:41:56PM +0000, Stanislav Kinsburskii wrote: > When Microsoft Hypervisor is active, the kernel may have memory “deposited” > to the hypervisor. Those pages are no longer safe for the kernel to touch, > and attempting to access them can trigger a GPF. The problem becomes acute > with kexec: the “deposited pages” state does not survive the transition, > and the next kernel has no reliable way to know which pages are still > owned/managed by the hypervisor. > > Until there is a proper handoff mechanism to preserve that state across > kexec, the only safe behavior is to refuse kexec whenever there is shared > hypervisor state that cannot survive the transition—most notably deposited > pages, and also cases where VMs are still running. > > This series adds the missing kexec integration point needed by MSHV: a > callback at the kexec “freeze” stage so the driver can make the transition > safe (or block it). With this hook, MSHV can refuse kexec while VMs are > running, attempt to withdraw deposited pages when possible (e.g. L1VH > host), and fail the transition if any pages remain deposited. > > --- > > Stanislav Kinsburskii (2): > kexec: Add permission notifier chain for kexec operations > mshv: Add kexec blocking support >
Hi, I’m sending a gentle follow‑up on the patch series below, which I posted about two weeks ago. I wanted to check whether anyone has had a chance to look at it, or if there are concerns I should address. Any feedback would be appreciated. Thanks for your time. Best regards, Stanislav > > drivers/hv/Makefile | 1 + > drivers/hv/hv_proc.c | 4 ++ > drivers/hv/mshv_kexec.c | 66 > ++++++++++++++++++++++++++++++++++++++++ > drivers/hv/mshv_root.h | 14 ++++++++ > drivers/hv/mshv_root_hv_call.c | 2 + > drivers/hv/mshv_root_main.c | 7 ++++ > include/linux/kexec.h | 6 ++++ > kernel/kexec_core.c | 24 +++++++++++++++ > 8 files changed, 124 insertions(+) > create mode 100644 drivers/hv/mshv_kexec.c >
