| Message ID | 20250113020925.18789-1-yan.y.zhao@intel.com (mailing list archive) |
|---|---|
| Headers | show |
| Series | KVM: TDX SEPT SEAMCALL retry | expand |
We should probably... On Mon, 2025-01-13 at 10:09 +0800, Yan Zhao wrote: > KVM: TDX: Return -EBUSY when tdh_mem_page_add() encounters > TDX_OPERAND_BUSY Squash this in "KVM: TDX: Add an ioctl to create initial guest memory" in kvm-coco-queue. > KVM: x86/mmu: Return RET_PF* instead of 1 in kvm_mmu_page_fault() Recommend this to go through kvm/x86 tree separately? > KVM: TDX: Retry locally in TDX EPT violation handler on RET_PF_RETRY > KVM: TDX: Kick off vCPUs when SEAMCALL is busy during TD page removal Include these in kvm-coco-queue and drop "x86/virt/tdx: Retry seamcall when TDX_OPERAND_BUSY with operand SEPT" > fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU > mirror page table > fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU > mirror page table Squash these into kvm-coco-queue. > fixup! KVM: TDX: Implement TDX vcpu enter/exit path Add this in the next version of "TDX vcpu enter/exit path". How does that sound?
On 1/13/25 03:09, Yan Zhao wrote: > This series aims to provide a clean solution to avoid the blind retries in > the previous hack [1] in "TDX MMU Part 2," following the initial > discussions to [2], further discussions in the RFC, and the PUCK [3]. > > A full analysis of the lock status for each SEAMCALL relevant to KVM is > available at [4]. > > This series categorizes the SEPT-related SEAMCALLs (used for page > installation and uninstallation) into three groups: > > Group 1: tdh_mem_page_add(). > - Invoked only during TD build time. > - Proposal: Return -EBUSY on TDX_OPERAND_BUSY. > - Patch 1. > > Group 2: tdh_mem_sept_add(), tdh_mem_page_aug(). > - Invoked for TD runtime page installation. > - Proposal: Retry locally in the TDX EPT violation handler for > RET_PF_RETRY. > - Patches 2-3. > > Group 3: tdh_mem_range_block(), tdh_mem_track(), tdh_mem_page_remove(). > - Invoked for page uninstallation, with KVM mmu_lock held for write. > - Proposal: Kick off vCPUs and no vCPU entry on TDX_OPERAND_BUSY. > - Patch 4. > > Patches 5/6/7 are fixup patches: > Patch 5: Return -EBUSY instead of -EAGAIN when tdh_mem_sept_add() is busy. > Patch 6: Remove the retry loop for tdh_phymem_page_wbinvd_hkid(). > Patch 7: Warn on force_immediate_exit in tdx_vcpu_run(). > > Code base: kvm-coco-queue 2f30b837bf7b. > Applies to the tail since the dependence on > commit 8e801e55ba8f ("KVM: TDX: Handle EPT violation/misconfig exit"), > > Thanks > Yan > > RFC --> v1: > - Split patch 1 in RFC into patches 1,2,3,5, and add new fixup patches 6/7. > - Add contention analysis of tdh_mem_page_add() in patch 1 log. > - Provide justification in patch 2 log and add checks for RET_PF_CONTINUE. > - Use "a per-VM flag wait_for_sept_zap + KVM_REQ_OUTSIDE_GUEST_MODE" > instead of a arch-specific request to prevent vCPUs from TD entry in patch 4 > (Sean). > > RFC: https://lore.kernel.org/all/20241121115139.26338-1-yan.y.zhao@intel.com > [1] https://lore.kernel.org/all/20241112073909.22326-1-yan.y.zhao@intel.com > [2] https://lore.kernel.org/kvm/20240904030751.117579-10-rick.p.edgecombe@intel.com/ > [3] https://drive.google.com/drive/folders/1k0qOarKuZXpzRsKDtVeC5Lpl9-amJ6AJ?resourcekey=0-l9uVpVEBC34Uar1ReaqisQ > [4] https://lore.kernel.org/kvm/ZuP5eNXFCljzRgWo@yzhao56-desk.sh.intel.com Thanks, I applied this to kvm-coco-queue and patch 2 to kvm/queue. It is spread all over the branch to make the dependencies clearer, so here's some ideas on how to include these. Patches 6 and 7 should be squashed into the respective bases, as they have essentially no functional change. For the rest, patch 1 can be treated as a fixup too, and I have two proposals. First possibility, separate series: * patches 1+5 are merged into a single patch. * patches 3+4 become two more patches in this separate series Second possibility, squash everything: * patches 1+5 are squashed into the respective bases * patches 3+4 are included in the EPT violation series On the PUCK call I said that I prefer the first, mostly to keep track of who needs to handle TDX_OPERAND_BUSY, but if it makes it easier for Yan then feel free to go for the second. Paolo > Yan Zhao (7): > KVM: TDX: Return -EBUSY when tdh_mem_page_add() encounters > TDX_OPERAND_BUSY > KVM: x86/mmu: Return RET_PF* instead of 1 in kvm_mmu_page_fault() > KVM: TDX: Retry locally in TDX EPT violation handler on RET_PF_RETRY > KVM: TDX: Kick off vCPUs when SEAMCALL is busy during TD page removal > fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU > mirror page table > fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU > mirror page table > fixup! KVM: TDX: Implement TDX vcpu enter/exit path > > arch/x86/kvm/mmu/mmu.c | 10 ++- > arch/x86/kvm/mmu/mmu_internal.h | 12 ++- > arch/x86/kvm/vmx/tdx.c | 135 ++++++++++++++++++++++++++------ > arch/x86/kvm/vmx/tdx.h | 7 ++ > 4 files changed, 134 insertions(+), 30 deletions(-) >
This series aims to provide a clean solution to avoid the blind retries in the previous hack [1] in "TDX MMU Part 2," following the initial discussions to [2], further discussions in the RFC, and the PUCK [3]. A full analysis of the lock status for each SEAMCALL relevant to KVM is available at [4]. This series categorizes the SEPT-related SEAMCALLs (used for page installation and uninstallation) into three groups: Group 1: tdh_mem_page_add(). - Invoked only during TD build time. - Proposal: Return -EBUSY on TDX_OPERAND_BUSY. - Patch 1. Group 2: tdh_mem_sept_add(), tdh_mem_page_aug(). - Invoked for TD runtime page installation. - Proposal: Retry locally in the TDX EPT violation handler for RET_PF_RETRY. - Patches 2-3. Group 3: tdh_mem_range_block(), tdh_mem_track(), tdh_mem_page_remove(). - Invoked for page uninstallation, with KVM mmu_lock held for write. - Proposal: Kick off vCPUs and no vCPU entry on TDX_OPERAND_BUSY. - Patch 4. Patches 5/6/7 are fixup patches: Patch 5: Return -EBUSY instead of -EAGAIN when tdh_mem_sept_add() is busy. Patch 6: Remove the retry loop for tdh_phymem_page_wbinvd_hkid(). Patch 7: Warn on force_immediate_exit in tdx_vcpu_run(). Code base: kvm-coco-queue 2f30b837bf7b. Applies to the tail since the dependence on commit 8e801e55ba8f ("KVM: TDX: Handle EPT violation/misconfig exit"), Thanks Yan RFC --> v1: - Split patch 1 in RFC into patches 1,2,3,5, and add new fixup patches 6/7. - Add contention analysis of tdh_mem_page_add() in patch 1 log. - Provide justification in patch 2 log and add checks for RET_PF_CONTINUE. - Use "a per-VM flag wait_for_sept_zap + KVM_REQ_OUTSIDE_GUEST_MODE" instead of a arch-specific request to prevent vCPUs from TD entry in patch 4 (Sean). RFC: https://lore.kernel.org/all/20241121115139.26338-1-yan.y.zhao@intel.com [1] https://lore.kernel.org/all/20241112073909.22326-1-yan.y.zhao@intel.com [2] https://lore.kernel.org/kvm/20240904030751.117579-10-rick.p.edgecombe@intel.com/ [3] https://drive.google.com/drive/folders/1k0qOarKuZXpzRsKDtVeC5Lpl9-amJ6AJ?resourcekey=0-l9uVpVEBC34Uar1ReaqisQ [4] https://lore.kernel.org/kvm/ZuP5eNXFCljzRgWo@yzhao56-desk.sh.intel.com Yan Zhao (7): KVM: TDX: Return -EBUSY when tdh_mem_page_add() encounters TDX_OPERAND_BUSY KVM: x86/mmu: Return RET_PF* instead of 1 in kvm_mmu_page_fault() KVM: TDX: Retry locally in TDX EPT violation handler on RET_PF_RETRY KVM: TDX: Kick off vCPUs when SEAMCALL is busy during TD page removal fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU mirror page table fixup! KVM: TDX: Implement hooks to propagate changes of TDP MMU mirror page table fixup! KVM: TDX: Implement TDX vcpu enter/exit path arch/x86/kvm/mmu/mmu.c | 10 ++- arch/x86/kvm/mmu/mmu_internal.h | 12 ++- arch/x86/kvm/vmx/tdx.c | 135 ++++++++++++++++++++++++++------ arch/x86/kvm/vmx/tdx.h | 7 ++ 4 files changed, 134 insertions(+), 30 deletions(-)