From: "Guo Ren (Alibaba DAMO Academy)" Previously the number of Hypervisor Guest External Interrupt (HGEI) lines was stored in a single global variable `kvm_riscv_aia_nr_hgei` and assumed to be the same for all HARTs. This assumption does not hold on heterogeneous RISC-V SoCs where different cores may expose different HGEIE CSR widths. Introduce `nr_hgei` field into the per-CPU `struct aia_hgei_control` and probe the actual supported HGEI count for the current HART in `kvm_riscv_aia_enable()` using the standard RISC-V CSR probe technique: csr_write(CSR_HGEIE, -1UL); nr = fls_long(csr_read(CSR_HGEIE)); if (nr) nr--; All HGEI allocation, free and disable paths (`kvm_riscv_aia_free_hgei()`, `kvm_riscv_aia_disable()`, etc.) now use the per-CPU value instead of the global one. The early global `kvm_riscv_aia_nr_hgei` is kept only for deciding whether SGEI interrupt registration is needed; the real per-HART initialization of lock and free_bitmap is moved to enable time. This makes KVM AIA robust on big.LITTLE-style and multi-vendor asymmetric platforms. Signed-off-by: Guo Ren (Alibaba DAMO Academy) --- arch/riscv/kvm/aia.c | 40 ++++++++++++++++++++++++---------------- 1 file changed, 24 insertions(+), 16 deletions(-) diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c index 5ec503288555..a23729052cfb 100644 --- a/arch/riscv/kvm/aia.c +++ b/arch/riscv/kvm/aia.c @@ -23,6 +23,7 @@ struct aia_hgei_control { raw_spinlock_t lock; unsigned long free_bitmap; struct kvm_vcpu *owners[BITS_PER_LONG]; + unsigned int nr_hgei; }; static DEFINE_PER_CPU(struct aia_hgei_control, aia_hgei); static int hgei_parent_irq; @@ -452,7 +453,7 @@ void kvm_riscv_aia_free_hgei(int cpu, int hgei) raw_spin_lock_irqsave(&hgctrl->lock, flags); - if (hgei > 0 && hgei <= kvm_riscv_aia_nr_hgei) { + if (hgei > 0 && hgei <= hgctrl->nr_hgei) { if (!(hgctrl->free_bitmap & BIT(hgei))) { hgctrl->free_bitmap |= BIT(hgei); hgctrl->owners[hgei] = NULL; @@ -486,21 +487,8 @@ static irqreturn_t hgei_interrupt(int irq, void *dev_id) static int aia_hgei_init(void) { - int cpu, rc; + int rc; struct irq_domain *domain; - struct aia_hgei_control *hgctrl; - - /* Initialize per-CPU guest external interrupt line management */ - for_each_possible_cpu(cpu) { - hgctrl = per_cpu_ptr(&aia_hgei, cpu); - raw_spin_lock_init(&hgctrl->lock); - if (kvm_riscv_aia_nr_hgei) { - hgctrl->free_bitmap = - BIT(kvm_riscv_aia_nr_hgei + 1) - 1; - hgctrl->free_bitmap &= ~BIT(0); - } else - hgctrl->free_bitmap = 0; - } /* Skip SGEI interrupt setup for zero guest external interrupts */ if (!kvm_riscv_aia_nr_hgei) @@ -545,9 +533,29 @@ static void aia_hgei_exit(void) void kvm_riscv_aia_enable(void) { + struct aia_hgei_control *hgctrl; + if (!kvm_riscv_aia_available()) return; + hgctrl = this_cpu_ptr(&aia_hgei); + + /* Figure-out number of bits in HGEIE */ + csr_write(CSR_HGEIE, -1UL); + hgctrl->nr_hgei = fls_long(csr_read(CSR_HGEIE)); + csr_write(CSR_HGEIE, 0); + if (hgctrl->nr_hgei) + hgctrl->nr_hgei--; + + if (hgctrl->nr_hgei) { + hgctrl->free_bitmap = BIT(hgctrl->nr_hgei + 1) - 1; + hgctrl->free_bitmap &= ~BIT(0); + } else { + hgctrl->free_bitmap = 0; + } + + raw_spin_lock_init(&hgctrl->lock); + csr_write(CSR_HVICTL, aia_hvictl_value(false)); csr_write(CSR_HVIPRIO1, 0x0); csr_write(CSR_HVIPRIO2, 0x0); @@ -588,7 +596,7 @@ void kvm_riscv_aia_disable(void) raw_spin_lock_irqsave(&hgctrl->lock, flags); - for (i = 0; i <= kvm_riscv_aia_nr_hgei; i++) { + for (i = 0; i <= hgctrl->nr_hgei; i++) { vcpu = hgctrl->owners[i]; if (!vcpu) continue; -- 2.40.1 From: "Guo Ren (Alibaba DAMO Academy)" Now that HGEI line management is fully per-CPU (via struct aia_hgei_control::nr_hgei), the global `kvm_riscv_aia_nr_hgei` is no longer needed. Replace it with a simple `bool kvm_riscv_aia_hgei_enabled` that only indicates whether HGEI support is available at all. Signed-off-by: Guo Ren (Alibaba DAMO Academy) --- arch/riscv/include/asm/kvm_aia.h | 2 +- arch/riscv/kvm/aia.c | 18 ++++++++---------- arch/riscv/kvm/aia_device.c | 4 ++-- arch/riscv/kvm/main.c | 3 +-- 4 files changed, 12 insertions(+), 15 deletions(-) diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h index b04ecdd1a860..e8749ac6bed7 100644 --- a/arch/riscv/include/asm/kvm_aia.h +++ b/arch/riscv/include/asm/kvm_aia.h @@ -79,7 +79,7 @@ struct kvm_vcpu_aia { #define irqchip_in_kernel(k) ((k)->arch.aia.in_kernel) -extern unsigned int kvm_riscv_aia_nr_hgei; +extern bool kvm_riscv_aia_hgei_enabled; extern unsigned int kvm_riscv_aia_max_ids; DECLARE_STATIC_KEY_FALSE(kvm_riscv_aia_available); #define kvm_riscv_aia_available() \ diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c index a23729052cfb..70ff1d25dd99 100644 --- a/arch/riscv/kvm/aia.c +++ b/arch/riscv/kvm/aia.c @@ -28,7 +28,7 @@ struct aia_hgei_control { static DEFINE_PER_CPU(struct aia_hgei_control, aia_hgei); static int hgei_parent_irq; -unsigned int kvm_riscv_aia_nr_hgei; +bool kvm_riscv_aia_hgei_enabled; unsigned int kvm_riscv_aia_max_ids; DEFINE_STATIC_KEY_FALSE(kvm_riscv_aia_available); @@ -491,7 +491,7 @@ static int aia_hgei_init(void) struct irq_domain *domain; /* Skip SGEI interrupt setup for zero guest external interrupts */ - if (!kvm_riscv_aia_nr_hgei) + if (!kvm_riscv_aia_hgei_enabled) goto skip_sgei_interrupt; /* Find INTC irq domain */ @@ -524,7 +524,7 @@ static int aia_hgei_init(void) static void aia_hgei_exit(void) { /* Do nothing for zero guest external interrupts */ - if (!kvm_riscv_aia_nr_hgei) + if (!kvm_riscv_aia_hgei_enabled) return; /* Free per-CPU SGEI interrupt */ @@ -631,6 +631,7 @@ int kvm_riscv_aia_init(void) { int rc; const struct imsic_global_config *gc; + unsigned int kvm_riscv_aia_nr_hgei; if (!riscv_isa_extension_available(NULL, SxAIA)) return -ENODEV; @@ -641,21 +642,18 @@ int kvm_riscv_aia_init(void) kvm_riscv_aia_nr_hgei = fls_long(csr_read(CSR_HGEIE)); csr_write(CSR_HGEIE, 0); if (kvm_riscv_aia_nr_hgei) - kvm_riscv_aia_nr_hgei--; + kvm_riscv_aia_hgei_enabled = true; /* * Number of usable HGEI lines should be minimum of per-HART * IMSIC guest files and number of bits in HGEIE */ - if (gc) - kvm_riscv_aia_nr_hgei = min((ulong)kvm_riscv_aia_nr_hgei, - gc->nr_guest_files); - else - kvm_riscv_aia_nr_hgei = 0; + if (!gc) + kvm_riscv_aia_hgei_enabled = 0; /* Find number of guest MSI IDs */ kvm_riscv_aia_max_ids = IMSIC_MAX_ID; - if (gc && kvm_riscv_aia_nr_hgei) + if (gc && kvm_riscv_aia_hgei_enabled) kvm_riscv_aia_max_ids = gc->nr_guest_ids + 1; /* Initialize guest external interrupt line management */ diff --git a/arch/riscv/kvm/aia_device.c b/arch/riscv/kvm/aia_device.c index 3d1e81e2a36b..5b45b1114425 100644 --- a/arch/riscv/kvm/aia_device.c +++ b/arch/riscv/kvm/aia_device.c @@ -71,7 +71,7 @@ static int aia_config(struct kvm *kvm, unsigned long type, * external interrupts (i.e. non-zero * VS-level IMSIC pages). */ - if (!kvm_riscv_aia_nr_hgei) + if (!kvm_riscv_aia_hgei_enabled) return -EINVAL; break; default: @@ -628,7 +628,7 @@ void kvm_riscv_aia_init_vm(struct kvm *kvm) */ /* Initialize default values in AIA global context */ - aia->mode = (kvm_riscv_aia_nr_hgei) ? + aia->mode = (kvm_riscv_aia_hgei_enabled) ? KVM_DEV_RISCV_AIA_MODE_AUTO : KVM_DEV_RISCV_AIA_MODE_EMUL; aia->nr_ids = kvm_riscv_aia_max_ids - 1; aia->nr_sources = 0; diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c index cb8a65273c1f..bcfa139f4871 100644 --- a/arch/riscv/kvm/main.c +++ b/arch/riscv/kvm/main.c @@ -169,8 +169,7 @@ static int __init riscv_kvm_init(void) kvm_info("VMID %ld bits available\n", kvm_riscv_gstage_vmid_bits()); if (kvm_riscv_aia_available()) - kvm_info("AIA available with %d guest external interrupts\n", - kvm_riscv_aia_nr_hgei); + kvm_info("AIA available with guest external interrupts\n"); kvm_riscv_setup_vendor_features(); -- 2.40.1 From: "Guo Ren (Alibaba DAMO Academy)" With the recent KVM AIA changes, HGEI line management is now fully per-CPU (via struct aia_hgei_control::nr_hgei) and the global kvm_riscv_aia_nr_hgei has been replaced by a simple enabled flag. The IMSIC driver no longer needs to compute and enforce a global minimum number of guest interrupt files across all HARTs. Remove: - `u32 nr_guest_files` from `struct imsic_global_config` - the initial `BIT(global->guest_index_bits) - 1` assignment - the entire per-CPU MMIO-based min() calculation and its comment (which was specifically there to protect old KVM) The per-HART guest file count is already handled locally in `imsic_local_config` during the parent IRQ loop, so this global field was redundant. This completes the cleanup series, eliminates the last global assumption about guest files, and improves support for heterogeneous (big.LITTLE / multi-vendor) RISC-V platforms. Signed-off-by: Guo Ren (Alibaba DAMO Academy) --- drivers/irqchip/irq-riscv-imsic-state.c | 12 +----------- include/linux/irqchip/riscv-imsic.h | 3 --- 2 files changed, 1 insertion(+), 14 deletions(-) diff --git a/drivers/irqchip/irq-riscv-imsic-state.c b/drivers/irqchip/irq-riscv-imsic-state.c index e3ed874d89e7..fef27247a34f 100644 --- a/drivers/irqchip/irq-riscv-imsic-state.c +++ b/drivers/irqchip/irq-riscv-imsic-state.c @@ -784,7 +784,7 @@ static int __init imsic_parse_fwnode(struct fwnode_handle *fwnode, int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque) { - u32 i, j, index, nr_parent_irqs, nr_mmios, nr_guest_files, nr_handlers = 0; + u32 i, j, index, nr_parent_irqs, nr_mmios, nr_handlers = 0; struct imsic_global_config *global; struct imsic_local_config *local; void __iomem **mmios_va = NULL; @@ -878,7 +878,6 @@ int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque) } /* Configure handlers for target CPUs */ - global->nr_guest_files = BIT(global->guest_index_bits) - 1; for (i = 0; i < nr_parent_irqs; i++) { rc = imsic_get_parent_hartid(fwnode, i, &hartid); if (rc) { @@ -919,15 +918,6 @@ int __init imsic_setup_state(struct fwnode_handle *fwnode, void *opaque) local->msi_pa = mmios[index].start + reloff; local->msi_va = mmios_va[index] + reloff; - /* - * KVM uses global->nr_guest_files to determine the available guest - * interrupt files on each CPU. Take the minimum number of guest - * interrupt files across all CPUs to avoid KVM incorrectly allocating - * an unexisted or unmapped guest interrupt file on some CPUs. - */ - nr_guest_files = (resource_size(&mmios[index]) - reloff) / IMSIC_MMIO_PAGE_SZ - 1; - global->nr_guest_files = min(global->nr_guest_files, nr_guest_files); - nr_handlers++; } diff --git a/include/linux/irqchip/riscv-imsic.h b/include/linux/irqchip/riscv-imsic.h index 4b348836de7a..7f3ff5c5ea53 100644 --- a/include/linux/irqchip/riscv-imsic.h +++ b/include/linux/irqchip/riscv-imsic.h @@ -68,9 +68,6 @@ struct imsic_global_config { /* Number of guest interrupt identities */ u32 nr_guest_ids; - /* Number of guest interrupt files per core */ - u32 nr_guest_files; - /* Per-CPU IMSIC addresses */ struct imsic_local_config __percpu *local; }; -- 2.40.1