On Thu, May 08, 2025 at 04:23:56PM +0300, Kirill A. Shutemov wrote: > On Tue, May 06, 2025 at 07:55:17PM +0800, Yan Zhao wrote: > > On Fri, May 02, 2025 at 04:08:24PM +0300, Kirill A. Shutemov wrote: > > > The functions kvm_x86_ops::link_external_spt() and > > > kvm_x86_ops::set_external_spte() are used to assign new memory to a VM. > > > When using TDX with Dynamic PAMT enabled, the assigned memory must be > > > covered by PAMT. > > > > > > The new function kvm_x86_ops::phys_prepare() is called before > > > link_external_spt() and set_external_spte() to ensure that the memory is > > > ready to be assigned to the virtual machine. In the case of TDX, it > > > makes sure that the memory is covered by PAMT. > > > > > > kvm_x86_ops::phys_prepare() is called in a context where struct kvm_vcpu > > > is available, allowing the implementation to allocate memory from a > > > per-VCPU pool. > > > > > Why not invoke phys_prepare() and phys_cleanup() in set_external_spte_present()? > > Or in tdx_sept_set_private_spte()/tdx_sept_link_private_spt()? > > Because the memory pool we allocated from is per-vcpu and we lost access > to vcpu by then. And not all callers provide vcpu. Maybe we can get vcpu via kvm_get_running_vcpu(), as in [1]. Then for callers not providing vcpu (where vcpu is NULL), we can use per-KVM cache? [1] https://lore.kernel.org/all/20250424030926.554-1-yan.y.zhao@xxxxxxxxx/
