Re: [PATCH 0/5] KVM: SEV: Drop user-triggerable WARN clean up REG_REGION

[Sean Christopherson]

On Thu, 12 Mar 2026 17:32:57 -0700, Sean Christopherson wrote:
> Drop a WARN in sev_pin_memory() that is comically easy to trigger, and then
> clean up the code a bit.
> 
> *** WARNING ***
> 
> The last patch impacts KVM's ABI due to a size restriction that's applied to
> kvmalloc() but not vmalloc().  If my math is correct (definitely a big "if),
> it will only impact VMMs that attempt to do KVM_MEMORY_ENCRYPT_REG_REGION with
> a single region of ~1TiB+.
> 
> [...]

Applied to kvm-x86 svm.  Like the other large set of SEV fixes, I'll omit this
from the pull request if there are any problems.

[1/5] KVM: SEV: Drop WARN on large size for KVM_MEMORY_ENCRYPT_REG_REGION
      https://github.com/kvm-x86/linux/commit/8acffeef5ef7
[2/5] KVM: SEV: Drop useless sanity checks in sev_mem_enc_register_region()
      https://github.com/kvm-x86/linux/commit/12a8ff869ddc
[3/5] KVM: SEV: Disallow pinning more pages than exist in the system
      https://github.com/kvm-x86/linux/commit/6d71f9349d9b
[4/5] KVM: SEV: Use PFN_DOWN() to simplify "number of pages" math when pinning memory
      https://github.com/kvm-x86/linux/commit/7ad02ff1e4a4
[5/5] KVM: SEV: Use kvzalloc_objs() when pinning userpages
      https://github.com/kvm-x86/linux/commit/a7f53694d591

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