Replace linear searches over all vCPUs in MSI injection paths with a hart_index -> vCPU xarray lookup table. This avoids O(n) scans on every injected interrupt and improves performance when the number of vCPUs is large. Both kvm_riscv_aia_inject_msi_by_id() and kvm_riscv_aia_inject_msi() now use the table instead of iterating over the vCPU list. Signed-off-by: BillXiang Changes in v2: - Use xarray instead of normal array to handle incontiguous hart_index. - Link to v1: https://lore.kernel.org/kvm-riscv/20260730093614.983508-1-xiangwencheng@lanxincomputing.com/ --- arch/riscv/include/asm/kvm_aia.h | 3 ++ arch/riscv/kvm/aia_device.c | 50 +++++++++++++++++--------------- 2 files changed, 30 insertions(+), 23 deletions(-) diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h index ab03f853e507..3b075f18e1d6 100644 --- a/arch/riscv/include/asm/kvm_aia.h +++ b/arch/riscv/include/asm/kvm_aia.h @@ -12,6 +12,7 @@ #include #include +#include #include struct kvm_aia { @@ -47,6 +48,8 @@ struct kvm_aia { /* Internal state of APLIC */ void *aplic_state; + + struct xarray hart_to_vcpu; }; struct kvm_vcpu_aia_csr { diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c index efc7c0bcfba9..a415a8c10967 100644 --- a/arch/riscv/kvm/aia_device.c +++ b/arch/riscv/kvm/aia_device.c @@ -259,6 +259,8 @@ static int aia_init(struct kvm *kvm) if (ret) return ret; + xa_init(&aia->hart_to_vcpu); + /* Iterate over each VCPU */ kvm_for_each_vcpu(idx, vcpu, kvm) { vaia = &vcpu->arch.aia_context; @@ -280,6 +282,11 @@ static int aia_init(struct kvm *kvm) /* Update HART index of the IMSIC based on IMSIC base */ vaia->hart_index = aia_imsic_hart_index(aia, vaia->imsic_addr); + + ret = xa_insert(&aia->hart_to_vcpu, vaia->hart_index, vcpu, GFP_KERNEL); + if (ret) { + goto fail_cleanup_imsics; + } /* Initialize IMSIC for this VCPU */ ret = kvm_riscv_vcpu_aia_imsic_init(vcpu); @@ -299,6 +306,7 @@ static int aia_init(struct kvm *kvm) continue; kvm_riscv_vcpu_aia_imsic_cleanup(vcpu); } + xa_destroy(&aia->hart_to_vcpu); kvm_riscv_aia_aplic_cleanup(kvm); return ret; } @@ -557,30 +565,25 @@ void kvm_riscv_vcpu_aia_deinit(struct kvm_vcpu *vcpu) int kvm_riscv_aia_inject_msi_by_id(struct kvm *kvm, u32 hart_index, u32 guest_index, u32 iid) { - unsigned long idx; struct kvm_vcpu *vcpu; + struct kvm_aia *aia = &kvm->arch.aia; /* Proceed only if AIA was initialized successfully */ if (!kvm_riscv_aia_initialized(kvm)) return -EBUSY; - /* Inject MSI to matching VCPU */ - kvm_for_each_vcpu(idx, vcpu, kvm) { - if (vcpu->arch.aia_context.hart_index == hart_index) - return kvm_riscv_vcpu_aia_imsic_inject(vcpu, - guest_index, - 0, iid); - } - - return 0; + vcpu = xa_load(&aia->hart_to_vcpu, hart_index); + if (!vcpu) + return 0; + + return kvm_riscv_vcpu_aia_imsic_inject(vcpu, guest_index, 0, iid); } int kvm_riscv_aia_inject_msi(struct kvm *kvm, struct kvm_msi *msi) { gpa_t tppn, ippn; - unsigned long idx; struct kvm_vcpu *vcpu; - u32 g, toff, iid = msi->data; + u32 g, toff, iid = msi->data, hart_index; struct kvm_aia *aia = &kvm->arch.aia; gpa_t target = (((gpa_t)msi->address_hi) << 32) | msi->address_lo; @@ -595,18 +598,16 @@ int kvm_riscv_aia_inject_msi(struct kvm *kvm, struct kvm_msi *msi) g = tppn & (BIT(aia->nr_guest_bits) - 1); tppn &= ~((gpa_t)(BIT(aia->nr_guest_bits) - 1)); - /* Inject MSI to matching VCPU */ - kvm_for_each_vcpu(idx, vcpu, kvm) { - ippn = vcpu->arch.aia_context.imsic_addr >> - IMSIC_MMIO_PAGE_SHIFT; - if (ippn == tppn) { - toff = target & (IMSIC_MMIO_PAGE_SZ - 1); - return kvm_riscv_vcpu_aia_imsic_inject(vcpu, g, - toff, iid); - } - } + hart_index = aia_imsic_hart_index(aia, target); + vcpu = xa_load(&aia->hart_to_vcpu, hart_index); + if (!vcpu) + return 0; - return 0; + ippn = vcpu->arch.aia_context.imsic_addr >> IMSIC_MMIO_PAGE_SHIFT; + if (ippn != tppn) + return 0; + toff = target & (IMSIC_MMIO_PAGE_SZ - 1); + return kvm_riscv_vcpu_aia_imsic_inject(vcpu, g, toff, iid); } int kvm_riscv_aia_inject_irq(struct kvm *kvm, unsigned int irq, bool level) @@ -647,9 +648,12 @@ void kvm_riscv_aia_init_vm(struct kvm *kvm) void kvm_riscv_aia_destroy_vm(struct kvm *kvm) { + struct kvm_aia *aia = &kvm->arch.aia; /* Proceed only if AIA was initialized successfully */ if (!kvm_riscv_aia_initialized(kvm)) return; + + xa_destroy(&aia->hart_to_vcpu); /* Cleanup APLIC context */ kvm_riscv_aia_aplic_cleanup(kvm); -- 2.53.0