On 5/23/25 02:59, Sean Christopherson wrote:
TL;DR: Overhaul device posted interrupts in KVM and IOMMU, and AVIC in
general.
This applies on the series to add CONFIG_KVM_IOAPIC (and to kill irq_comm.c):
https://lore.kernel.org/all/20250519232808.2745331-1-seanjc@xxxxxxxxxx
Fix a variety of bugs related to device posted IRQs, especially on the
AMD side, and clean up KVM's implementation (this series actually removes
more code than it adds).
Stating the obvious, this series is comically large. Though it's smaller than
v1! (Ignoring that I cheated by moving 15 patches to a prep series, and that
Paolo already grabbed several patches).
Sairaj, I applied your Tested-by somewhat sparingly, as some of the patches
changed (most notably "Consolidate IRTE update when toggling AVIC on/off").
Please holler if you want me to remove/add any tags. And when you get time,
I'd greatly appreciate a sanity check!
Batch #1 is mostly SVM specific:
- Cleans up various warts and bugs in the IRTE tracking
- Fixes AVIC to not reject large VMs (honor KVM's ABI)
- Wire up AVIC to enable_ipiv to support disabling IPI virtualization while
still utilizing device posted interrupts, and to workaround erratum #1235.
Batch #3 overhauls the guts of IRQ bypass in KVM, and moves the vast majority
of the logic to common x86; only the code that needs to communicate with the
IOMMU is truly vendor specific.
Batch #4 is more SVM/AVIC cleanups that are made possible by batch #3.
Batch #5 adds WARNs and drops dead code after all the previous cleanups and
fixes (I don't want to add the WARNs earlier; I don't see any point in adding
WARNs in code that's known to be broken).
Batch #6 is yet more SVM/AVIC cleanups, with the specific goal of configuring
IRTEs to generate GA log interrupts if and only if KVM actually needs a wake
event.
Looks good - it's not even that different from v1. Thanks!
Paolo
v2:
- Drop patches that were already merged.
- Move code into irq.c, not x86.c. [Paolo]
- Collect review/testing tags. [Sairaj, Vasant]
- Sqaush fixup for a comment that was added in the prior patch. [Sairaj]
- Rewrote the changelog for "Delete IRTE link from previous vCPU irrespective
of new routing". [Sairaj]
- Actually drop "struct amd_svm_iommu_ir" and all usage in "Track per-vCPU
IRTEs using kvm_kernel_irqfd structure" (the previous version was getting
hilarious lucky with struct offsets). [Sairaj]
- Drop unused params from kvm_pi_update_irte() and pi_update_irte(). [Sairaj]
- Document the rules and behavior of amd_iommu_update_ga(). [Joerg]
- Fix a changelog typo. [Paolo]
- Document that GALogIntr isn't cached, i.e. can be safely updated without
an invalidation. [Joao, Vasant]
- Rework avic_vcpu_{load,put}() to use an enumerated parameter instead of a
series of booleans. [Paolo]
- Drop a redundant "&& new". [Francesco]
- Drop the *** DO NOT MERGE *** testing hack patches.
v1: https://lore.kernel.org/all/20250404193923.1413163-1-seanjc@xxxxxxxxxx
Maxim Levitsky (2):
KVM: SVM: Add enable_ipiv param, never set IsRunning if disabled
KVM: SVM: Disable (x2)AVIC IPI virtualization if CPU has erratum #1235
Sean Christopherson (57):
KVM: x86: Pass new routing entries and irqfd when updating IRTEs
KVM: SVM: Track per-vCPU IRTEs using kvm_kernel_irqfd structure
KVM: SVM: Delete IRTE link from previous vCPU before setting new IRTE
iommu/amd: KVM: SVM: Delete now-unused cached/previous GA tag fields
KVM: SVM: Delete IRTE link from previous vCPU irrespective of new
routing
KVM: SVM: Drop pointless masking of default APIC base when setting
V_APIC_BAR
KVM: SVM: Drop pointless masking of kernel page pa's with AVIC HPA
masks
KVM: SVM: Add helper to deduplicate code for getting AVIC backing page
KVM: SVM: Drop vcpu_svm's pointless avic_backing_page field
KVM: SVM: Inhibit AVIC if ID is too big instead of rejecting vCPU
creation
KVM: SVM: Drop redundant check in AVIC code on ID during vCPU creation
KVM: SVM: Track AVIC tables as natively sized pointers, not "struct
pages"
KVM: SVM: Drop superfluous "cache" of AVIC Physical ID entry pointer
KVM: VMX: Move enable_ipiv knob to common x86
KVM: VMX: Suppress PI notifications whenever the vCPU is put
KVM: SVM: Add a comment to explain why avic_vcpu_blocking() ignores
IRQ blocking
iommu/amd: KVM: SVM: Use pi_desc_addr to derive ga_root_ptr
iommu/amd: KVM: SVM: Pass NULL @vcpu_info to indicate "not guest mode"
KVM: SVM: Stop walking list of routing table entries when updating
IRTE
KVM: VMX: Stop walking list of routing table entries when updating
IRTE
KVM: SVM: Extract SVM specific code out of get_pi_vcpu_info()
KVM: x86: Move IRQ routing/delivery APIs from x86.c => irq.c
KVM: x86: Nullify irqfd->producer after updating IRTEs
KVM: x86: Dedup AVIC vs. PI code for identifying target vCPU
KVM: x86: Move posted interrupt tracepoint to common code
KVM: SVM: Clean up return handling in avic_pi_update_irte()
iommu: KVM: Split "struct vcpu_data" into separate AMD vs. Intel
structs
KVM: Don't WARN if updating IRQ bypass route fails
KVM: Fold kvm_arch_irqfd_route_changed() into
kvm_arch_update_irqfd_routing()
KVM: x86: Track irq_bypass_vcpu in common x86 code
KVM: x86: Skip IOMMU IRTE updates if there's no old or new vCPU being
targeted
KVM: x86: Don't update IRTE entries when old and new routes were !MSI
KVM: SVM: Revert IRTE to legacy mode if IOMMU doesn't provide IR
metadata
KVM: SVM: Take and hold ir_list_lock across IRTE updates in IOMMU
iommu/amd: Document which IRTE fields amd_iommu_update_ga() can modify
iommu/amd: KVM: SVM: Infer IsRun from validity of pCPU destination
iommu/amd: Factor out helper for manipulating IRTE GA/CPU info
iommu/amd: KVM: SVM: Set pCPU info in IRTE when setting vCPU affinity
iommu/amd: KVM: SVM: Add IRTE metadata to affined vCPU's list if AVIC
is inhibited
KVM: SVM: Don't check for assigned device(s) when updating affinity
KVM: SVM: Don't check for assigned device(s) when activating AVIC
KVM: SVM: WARN if (de)activating guest mode in IOMMU fails
KVM: SVM: Process all IRTEs on affinity change even if one update
fails
KVM: SVM: WARN if updating IRTE GA fields in IOMMU fails
KVM: x86: Drop superfluous "has assigned device" check in
kvm_pi_update_irte()
KVM: x86: WARN if IRQ bypass isn't supported in kvm_pi_update_irte()
KVM: x86: WARN if IRQ bypass routing is updated without in-kernel
local APIC
KVM: SVM: WARN if ir_list is non-empty at vCPU free
KVM: x86: Decouple device assignment from IRQ bypass
KVM: VMX: WARN if VT-d Posted IRQs aren't possible when starting IRQ
bypass
KVM: SVM: Use vcpu_idx, not vcpu_id, for GA log tag/metadata
iommu/amd: WARN if KVM calls GA IRTE helpers without virtual APIC
support
KVM: SVM: Fold avic_set_pi_irte_mode() into its sole caller
KVM: SVM: Don't check vCPU's blocking status when toggling AVIC on/off
KVM: SVM: Consolidate IRTE update when toggling AVIC on/off
iommu/amd: KVM: SVM: Allow KVM to control need for GA log interrupts
KVM: SVM: Generate GA log IRQs only if the associated vCPUs is
blocking
arch/x86/include/asm/irq_remapping.h | 17 +-
arch/x86/include/asm/kvm-x86-ops.h | 2 +-
arch/x86/include/asm/kvm_host.h | 20 +-
arch/x86/include/asm/svm.h | 13 +-
arch/x86/kvm/irq.c | 140 ++++++
arch/x86/kvm/svm/avic.c | 702 ++++++++++++---------------
arch/x86/kvm/svm/svm.c | 4 +
arch/x86/kvm/svm/svm.h | 32 +-
arch/x86/kvm/trace.h | 19 +-
arch/x86/kvm/vmx/capabilities.h | 1 -
arch/x86/kvm/vmx/main.c | 2 +-
arch/x86/kvm/vmx/posted_intr.c | 140 ++----
arch/x86/kvm/vmx/posted_intr.h | 10 +-
arch/x86/kvm/vmx/vmx.c | 2 -
arch/x86/kvm/x86.c | 90 +---
drivers/iommu/amd/amd_iommu_types.h | 1 -
drivers/iommu/amd/iommu.c | 125 +++--
drivers/iommu/intel/irq_remapping.c | 10 +-
include/linux/amd-iommu.h | 25 +-
include/linux/kvm_host.h | 9 +-
include/linux/kvm_irqfd.h | 4 +
virt/kvm/eventfd.c | 22 +-
22 files changed, 672 insertions(+), 718 deletions(-)
base-commit: 3debd5461fba1dcb33e732b16153da0cf5d0c251
