Allocate the hashed list of shadow pages dynamically (separate from
struct kvm), and on-demand. The hashed list is 32KiB, i.e. absolutely
belongs in a separate allocation, and is worth skipping if KVM isn't
shadowing guest PTEs for the VM.
I double checked that padding kvm_arch with a 4KiB array trips the assert,
but padding with 2KiB does not. So knock on wood, I finally got the assert
right. Maybe.
v4:
- Use smp_store_release() and smp_load_acquire() instead of {READ,WRITE}_ONCE,
and update the comments accordingly. [Paolo, James]
- Move the kvm_tdx assert to tdx.c. [Paolo]
- Fix the assertion, again. [Vipin, in spirit if not in reality]
- Add a patch to move TDX hardware setup to tdx.c.
v3:
- https://lore.kernel.org/all/20250516215422.2550669-1-seanjc@google.com
- Add comments explaining the {READ,WRITE}_ONCE logic, and why it's safe
to set the list outside of mmu_lock. [Vipin]
- Make the assertions actually work. [Vipin]
- Refine the assertions so they (hopefully) won't fail on kernels with
a bunch of debug crud added.
v2:
- https://lore.kernel.org/all/20250401155714.838398-1-seanjc@google.com
- Actually defer allocation when using TDP MMU. [Vipin]
- Free allocation on MMU teardown. [Vipin]
v1: https://lore.kernel.org/all/20250315024010.2360884-1-seanjc@google.com
Sean Christopherson (4):
KVM: TDX: Move TDX hardware setup from main.c to tdx.c
KVM: x86/mmu: Dynamically allocate shadow MMU's hashed page list
KVM: x86: Use kvzalloc() to allocate VM struct
KVM: x86/mmu: Defer allocation of shadow MMU's hashed page list
arch/x86/include/asm/kvm_host.h | 6 +--
arch/x86/kvm/mmu/mmu.c | 75 ++++++++++++++++++++++++++++++---
arch/x86/kvm/svm/svm.c | 2 +
arch/x86/kvm/vmx/main.c | 36 +---------------
arch/x86/kvm/vmx/tdx.c | 47 +++++++++++++++------
arch/x86/kvm/vmx/tdx.h | 1 +
arch/x86/kvm/vmx/vmx.c | 2 +
arch/x86/kvm/vmx/x86_ops.h | 10 -----
arch/x86/kvm/x86.c | 5 ++-
arch/x86/kvm/x86.h | 22 ++++++++++
10 files changed, 139 insertions(+), 67 deletions(-)
base-commit: 3f7b307757ecffc1c18ede9ee3cf9ce8101f3cc9
--
2.49.0.1151.ga128411c76-goog