On Sat, Jan 14, 2023 at 12:37:59AM +0000, Sean Christopherson wrote:

On Fri, Dec 02, 2022, Chao Peng wrote:

quoted

This patch series implements KVM guest private memory for confidential
computing scenarios like Intel TDX[1]. If a TDX host accesses
TDX-protected guest memory, machine check can happen which can further
crash the running host system, this is terrible for multi-tenant
configurations. The host accesses include those from KVM userspace like
QEMU. This series addresses KVM userspace induced crash by introducing
new mm and KVM interfaces so KVM userspace can still manage guest memory
via a fd-based approach, but it can never access the guest memory
content.

The patch series touches both core mm and KVM code. I appreciate
Andrew/Hugh and Paolo/Sean can review and pick these patches. Any other
reviews are always welcome.
  - 01: mm change, target for mm tree
  - 02-09: KVM change, target for KVM tree

A version with all of my feedback, plus reworked versions of Vishal's selftest,
is available here:

  git@github.com:sean-jc/linux.git x86/upm_base_support

It compiles and passes the selftest, but it's otherwise barely tested.  There are
a few todos (2 I think?) and many of the commits need changelogs, i.e. it's still
a WIP.

As for next steps, can you (handwaving all of the TDX folks) take a look at what
I pushed and see if there's anything horrifically broken, and that it still works
for TDX?

Minor build fix:

diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c
index 6eb5336ccc65..4a9e9fa2552a 100644
--- a/arch/x86/kvm/mmu/mmu.c
+++ b/arch/x86/kvm/mmu/mmu.c

@@ -7211,8 +7211,8 @@ void kvm_arch_set_memory_attributes(struct kvm *kvm,
 	int level;
 	bool mixed;
 
-	lockdep_assert_held_write(kvm->mmu_lock);
-	lockdep_assert_held(kvm->slots_lock);
+	lockdep_assert_held_write(&kvm->mmu_lock);
+	lockdep_assert_held(&kvm->slots_lock);
 
 	/*
 	 * KVM x86 currently only supports KVM_MEMORY_ATTRIBUTE_PRIVATE, skip

diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
index 467916943c73..4ef60ba7eb1d 100644
--- a/include/linux/kvm_host.h
+++ b/include/linux/kvm_host.h

@@ -2304,7 +2304,7 @@ static inline void kvm_account_pgtable_pages(void *virt, int nr)
 #ifdef CONFIG_KVM_GENERIC_MEMORY_ATTRIBUTES
 static inline unsigned long kvm_get_memory_attributes(struct kvm *kvm, gfn_t gfn)
 {
-	lockdep_assert_held(kvm->mmu_lock);
+	lockdep_assert_held(&kvm->mmu_lock);
 
 	return xa_to_value(xa_load(&kvm->mem_attr_array, gfn));
 }

-- 
  Kiryl Shutsemau / Kirill A. Shutemov