Re: [PATCH v7 08/11] KVM: TDX: Get/put PAMT pages when (un)mapping private memory

On Fri, Jul 17, 2026, Rick Edgecombe wrote:
> From: "Kirill A. Shutemov" <[email protected]>
> 
> Add Dynamic PAMT support to KVM's S-EPT MMU by "getting" a PAMT page when
> adding guest memory (PAGE.ADD or PAGE.AUG), and "putting" the page when
> removing guest memory (PAGE.REMOVE).
> 
> To access the per-vCPU PAMT caches without plumbing @vcpu throughout the
> TDP MMU, begrudgingly use kvm_get_running_vcpu() to get the vCPU, and bug
> the VM if KVM attempts to set an S-EPT leaf without an active vCPU.  KVM
> only supports creating _new_ mappings in page (pre)fault paths, all of
> which require an active vCPU.
> 
> The PAMT memory holds metadata for TDX protected memory. With Dynamic
> PAMT, PAMT_4K is allocated on demand. The kernel supplies the TDX module
> with a few pages that cover 2MB of host physical memory.
> 
> Releases are balanced via tdx_pamt_put(): every control-page free goes
> through tdx_free_control_page(), and guest data pages are put directly on
> the successful tdh_mem_page_remove() path and in the
> tdx_mem_page_add/aug() error path.
> 
> Signed-off-by: Kirill A. Shutemov <[email protected]>
> Co-developed-by: Sean Christopherson <[email protected]>
> Signed-off-by: Sean Christopherson <[email protected]>
> [rick: enhance log, reviewing, rebase, with help from AI tooling]
> Co-developed-by: Rick Edgecombe <[email protected]>
> Signed-off-by: Rick Edgecombe <[email protected]>
> Reviewed-by: Binbin Wu <[email protected]>
> Reviewed-by: Tony Lindgren <[email protected]>
> ---

With the nits fixed,

Acked-by: Sean Christopherson <[email protected]>