| Message ID | 20230403093310.2271142-9-apatel@ventanamicro.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | RISC-V KVM virtualize AIA CSRs | expand |
On Mon, Apr 03, 2023 at 03:03:10PM +0530, Anup Patel wrote: > The RISC-V host will have one guest external interrupt line for each > VS-level IMSICs associated with a HART. The guest external interrupt > lines are per-HART resources and hypervisor can use HGEIE, HGEIP, and > HIE CSRs to manage these guest external interrupt lines. > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > --- > arch/riscv/include/asm/kvm_aia.h | 10 ++ > arch/riscv/kvm/aia.c | 241 +++++++++++++++++++++++++++++++ > arch/riscv/kvm/main.c | 3 +- > arch/riscv/kvm/vcpu.c | 2 + > 4 files changed, 255 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h > index 1de0717112e5..0938e0cadf80 100644 > --- a/arch/riscv/include/asm/kvm_aia.h > +++ b/arch/riscv/include/asm/kvm_aia.h > @@ -44,10 +44,15 @@ struct kvm_vcpu_aia { > > #define irqchip_in_kernel(k) ((k)->arch.aia.in_kernel) > > +extern unsigned int kvm_riscv_aia_nr_hgei; > DECLARE_STATIC_KEY_FALSE(kvm_riscv_aia_available); > #define kvm_riscv_aia_available() \ > static_branch_unlikely(&kvm_riscv_aia_available) > > +static inline void kvm_riscv_vcpu_aia_imsic_release(struct kvm_vcpu *vcpu) > +{ > +} > + > #define KVM_RISCV_AIA_IMSIC_TOPEI (ISELECT_MASK + 1) > static inline int kvm_riscv_vcpu_aia_imsic_rmw(struct kvm_vcpu *vcpu, > unsigned long isel, > @@ -119,6 +124,11 @@ static inline void kvm_riscv_aia_destroy_vm(struct kvm *kvm) > { > } > > +int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner, > + void __iomem **hgei_va, phys_addr_t *hgei_pa); > +void kvm_riscv_aia_free_hgei(int cpu, int hgei); > +void kvm_riscv_aia_wakeon_hgei(struct kvm_vcpu *owner, bool enable); > + > void kvm_riscv_aia_enable(void); > void kvm_riscv_aia_disable(void); > int kvm_riscv_aia_init(void); > diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c > index d530912f28bc..1264783e7c4d 100644 > --- a/arch/riscv/kvm/aia.c > +++ b/arch/riscv/kvm/aia.c > @@ -7,11 +7,46 @@ > * Anup Patel <apatel@ventanamicro.com> > */ > > +#include <linux/bitops.h> > +#include <linux/irq.h> > +#include <linux/irqdomain.h> > #include <linux/kvm_host.h> > +#include <linux/percpu.h> > +#include <linux/spinlock.h> > #include <asm/hwcap.h> > > +struct aia_hgei_control { > + raw_spinlock_t lock; > + unsigned long free_bitmap; > + struct kvm_vcpu *owners[BITS_PER_LONG]; > +}; > +static DEFINE_PER_CPU(struct aia_hgei_control, aia_hgei); > +static int hgei_parent_irq; > + > +unsigned int kvm_riscv_aia_nr_hgei; > DEFINE_STATIC_KEY_FALSE(kvm_riscv_aia_available); > > +static int aia_find_hgei(struct kvm_vcpu *owner) > +{ > + int i, hgei; > + unsigned long flags; > + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); > + > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > + > + hgei = -1; > + for (i = 1; i <= kvm_riscv_aia_nr_hgei; i++) { > + if (hgctrl->owners[i] == owner) { > + hgei = i; > + break; > + } > + } > + > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > + > + return hgei; > +} > + > static void aia_set_hvictl(bool ext_irq_pending) > { > unsigned long hvictl; > @@ -55,6 +90,7 @@ void kvm_riscv_vcpu_aia_sync_interrupts(struct kvm_vcpu *vcpu) > > bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask) > { > + int hgei; > unsigned long seip; > > if (!kvm_riscv_aia_available()) > @@ -72,6 +108,10 @@ bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask) > if (!kvm_riscv_aia_initialized(vcpu->kvm) || !seip) > return false; > > + hgei = aia_find_hgei(vcpu); > + if (hgei > 0) > + return (csr_read(CSR_HGEIP) & BIT(hgei)) ? true : false; nit: return !!(csr_read(CSR_HGEIP) & BIT(hgei)) is a bit less verbose. > + > return false; > } > > @@ -343,6 +383,144 @@ int kvm_riscv_vcpu_aia_rmw_ireg(struct kvm_vcpu *vcpu, unsigned int csr_num, > return KVM_INSN_EXIT_TO_USER_SPACE; > } > > +int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner, > + void __iomem **hgei_va, phys_addr_t *hgei_pa) > +{ > + int ret = -ENOENT; > + unsigned long flags; > + struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu); > + > + if (!kvm_riscv_aia_available()) > + return -ENODEV; > + if (!hgctrl) > + return -ENODEV; nit: if (!kvm_riscv_aia_available() || !hgctrl) return -ENODEV; > + > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > + > + if (hgctrl->free_bitmap) { > + ret = __ffs(hgctrl->free_bitmap); > + hgctrl->free_bitmap &= ~BIT(ret); > + hgctrl->owners[ret] = owner; > + } > + > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > + > + /* TODO: To be updated later by AIA in-kernel irqchip support */ > + if (hgei_va) > + *hgei_va = NULL; > + if (hgei_pa) > + *hgei_pa = 0; > + > + return ret; > +} > + > +void kvm_riscv_aia_free_hgei(int cpu, int hgei) > +{ > + unsigned long flags; > + struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu); > + > + if (!kvm_riscv_aia_available() || !hgctrl) > + return; > + > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > + > + if (hgei > 0 && hgei <= kvm_riscv_aia_nr_hgei) { > + if (!(hgctrl->free_bitmap & BIT(hgei))) { > + hgctrl->free_bitmap |= BIT(hgei); > + hgctrl->owners[hgei] = NULL; > + } > + } > + > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > +} > + > +void kvm_riscv_aia_wakeon_hgei(struct kvm_vcpu *owner, bool enable) > +{ > + int hgei; > + > + if (!kvm_riscv_aia_available()) > + return; > + > + hgei = aia_find_hgei(owner); > + if (hgei > 0) { > + if (enable) > + csr_set(CSR_HGEIE, BIT(hgei)); > + else > + csr_clear(CSR_HGEIE, BIT(hgei)); > + } > +} > + > +static irqreturn_t hgei_interrupt(int irq, void *dev_id) > +{ > + int i; > + unsigned long hgei_mask, flags; > + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); > + > + hgei_mask = csr_read(CSR_HGEIP) & csr_read(CSR_HGEIE); > + csr_clear(CSR_HGEIE, hgei_mask); > + > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > + > + for_each_set_bit(i, &hgei_mask, BITS_PER_LONG) { > + if (hgctrl->owners[i]) > + kvm_vcpu_kick(hgctrl->owners[i]); > + } > + > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > + > + return IRQ_HANDLED; > +} > + > +static int aia_hgei_init(void) > +{ > + int cpu, 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; > + } > + > + /* Find INTC irq domain */ > + domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), > + DOMAIN_BUS_ANY); > + if (!domain) { > + kvm_err("unable to find INTC domain\n"); > + return -ENOENT; > + } > + > + /* Map per-CPU SGEI interrupt from INTC domain */ > + hgei_parent_irq = irq_create_mapping(domain, IRQ_S_GEXT); > + if (!hgei_parent_irq) { > + kvm_err("unable to map SGEI IRQ\n"); > + return -ENOMEM; > + } > + > + /* Request per-CPU SGEI interrupt */ > + rc = request_percpu_irq(hgei_parent_irq, hgei_interrupt, > + "riscv-kvm", &aia_hgei); > + if (rc) { > + kvm_err("failed to request SGEI IRQ\n"); > + return rc; > + } > + > + return 0; > +} > + > +static void aia_hgei_exit(void) > +{ > + /* Free per-CPU SGEI interrupt */ > + free_percpu_irq(hgei_parent_irq, &aia_hgei); > +} > + > void kvm_riscv_aia_enable(void) > { > if (!kvm_riscv_aia_available()) > @@ -357,21 +535,79 @@ void kvm_riscv_aia_enable(void) > csr_write(CSR_HVIPRIO1H, 0x0); > csr_write(CSR_HVIPRIO2H, 0x0); > #endif > + > + /* Enable per-CPU SGEI interrupt */ > + enable_percpu_irq(hgei_parent_irq, > + irq_get_trigger_type(hgei_parent_irq)); > + csr_set(CSR_HIE, BIT(IRQ_S_GEXT)); > } > > void kvm_riscv_aia_disable(void) > { > + int i; > + unsigned long flags; > + struct kvm_vcpu *vcpu; > + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); > + > if (!kvm_riscv_aia_available()) > return; > > + /* Disable per-CPU SGEI interrupt */ > + csr_clear(CSR_HIE, BIT(IRQ_S_GEXT)); > + disable_percpu_irq(hgei_parent_irq); > + > aia_set_hvictl(false); > + > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > + > + for (i = 0; i <= kvm_riscv_aia_nr_hgei; i++) { I guess this should start at i = 1, but in this case it doesn't matter since hgctrl->owners[0] should always be NULL. > + vcpu = hgctrl->owners[i]; > + if (!vcpu) > + continue; > + > + /* > + * We release hgctrl->lock before notifying IMSIC > + * so that we don't have lock ordering issues. > + */ > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > + > + /* Notify IMSIC */ > + kvm_riscv_vcpu_aia_imsic_release(vcpu); > + > + /* > + * Wakeup VCPU if it was blocked so that it can > + * run on other HARTs > + */ > + if (csr_read(CSR_HGEIE) & BIT(i)) { > + csr_clear(CSR_HGEIE, BIT(i)); > + kvm_vcpu_kick(vcpu); Doing all this outside the lock makes me wonder what happens when 'vcpu' is no longer the owner at the time of kvm_riscv_vcpu_aia_imsic_release() or kvm_vcpu_kick(). Even if the calls on the wrong vcpu are just noise, then don't we still need to confirm that we release/kick the real owner before we return from this function? It appears safe to call kvm_vcpu_kick() while holding the lock and hgei_interrupt() does that. So, since there's currently no implementation of kvm_riscv_vcpu_aia_imsic_release(), I'm not sure what lock ordering issues we need to avoid. > + } > + > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > + } > + > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > } > > int kvm_riscv_aia_init(void) > { > + int rc; > + > if (!riscv_isa_extension_available(NULL, SxAIA)) > return -ENODEV; > > + /* Figure-out number of bits in HGEIE */ > + csr_write(CSR_HGEIE, -1UL); > + 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--; > + > + /* Initialize guest external interrupt line management */ > + rc = aia_hgei_init(); > + if (rc) > + return rc; > + > /* Enable KVM AIA support */ > static_branch_enable(&kvm_riscv_aia_available); > > @@ -380,4 +616,9 @@ int kvm_riscv_aia_init(void) > > void kvm_riscv_aia_exit(void) > { > + if (!kvm_riscv_aia_available()) > + return; > + > + /* Cleanup the HGEI state */ > + aia_hgei_exit(); > } > diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c > index 6396352b4e4d..b0b46f48f31e 100644 > --- a/arch/riscv/kvm/main.c > +++ b/arch/riscv/kvm/main.c > @@ -116,7 +116,8 @@ 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\n"); > + kvm_info("AIA available with %d guest external interrupts\n", > + kvm_riscv_aia_nr_hgei); > > rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE); > if (rc) { > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c > index 30acf3ebdc3d..eace51dd896f 100644 > --- a/arch/riscv/kvm/vcpu.c > +++ b/arch/riscv/kvm/vcpu.c > @@ -249,10 +249,12 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) > > void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) > { > + kvm_riscv_aia_wakeon_hgei(vcpu, true); > } > > void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) > { > + kvm_riscv_aia_wakeon_hgei(vcpu, false); > } > > int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) > -- > 2.34.1 > Thanks, drew
On Tue, Apr 4, 2023 at 6:15 PM Andrew Jones <ajones@ventanamicro.com> wrote: > > On Mon, Apr 03, 2023 at 03:03:10PM +0530, Anup Patel wrote: > > The RISC-V host will have one guest external interrupt line for each > > VS-level IMSICs associated with a HART. The guest external interrupt > > lines are per-HART resources and hypervisor can use HGEIE, HGEIP, and > > HIE CSRs to manage these guest external interrupt lines. > > > > Signed-off-by: Anup Patel <apatel@ventanamicro.com> > > --- > > arch/riscv/include/asm/kvm_aia.h | 10 ++ > > arch/riscv/kvm/aia.c | 241 +++++++++++++++++++++++++++++++ > > arch/riscv/kvm/main.c | 3 +- > > arch/riscv/kvm/vcpu.c | 2 + > > 4 files changed, 255 insertions(+), 1 deletion(-) > > > > diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h > > index 1de0717112e5..0938e0cadf80 100644 > > --- a/arch/riscv/include/asm/kvm_aia.h > > +++ b/arch/riscv/include/asm/kvm_aia.h > > @@ -44,10 +44,15 @@ struct kvm_vcpu_aia { > > > > #define irqchip_in_kernel(k) ((k)->arch.aia.in_kernel) > > > > +extern unsigned int kvm_riscv_aia_nr_hgei; > > DECLARE_STATIC_KEY_FALSE(kvm_riscv_aia_available); > > #define kvm_riscv_aia_available() \ > > static_branch_unlikely(&kvm_riscv_aia_available) > > > > +static inline void kvm_riscv_vcpu_aia_imsic_release(struct kvm_vcpu *vcpu) > > +{ > > +} > > + > > #define KVM_RISCV_AIA_IMSIC_TOPEI (ISELECT_MASK + 1) > > static inline int kvm_riscv_vcpu_aia_imsic_rmw(struct kvm_vcpu *vcpu, > > unsigned long isel, > > @@ -119,6 +124,11 @@ static inline void kvm_riscv_aia_destroy_vm(struct kvm *kvm) > > { > > } > > > > +int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner, > > + void __iomem **hgei_va, phys_addr_t *hgei_pa); > > +void kvm_riscv_aia_free_hgei(int cpu, int hgei); > > +void kvm_riscv_aia_wakeon_hgei(struct kvm_vcpu *owner, bool enable); > > + > > void kvm_riscv_aia_enable(void); > > void kvm_riscv_aia_disable(void); > > int kvm_riscv_aia_init(void); > > diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c > > index d530912f28bc..1264783e7c4d 100644 > > --- a/arch/riscv/kvm/aia.c > > +++ b/arch/riscv/kvm/aia.c > > @@ -7,11 +7,46 @@ > > * Anup Patel <apatel@ventanamicro.com> > > */ > > > > +#include <linux/bitops.h> > > +#include <linux/irq.h> > > +#include <linux/irqdomain.h> > > #include <linux/kvm_host.h> > > +#include <linux/percpu.h> > > +#include <linux/spinlock.h> > > #include <asm/hwcap.h> > > > > +struct aia_hgei_control { > > + raw_spinlock_t lock; > > + unsigned long free_bitmap; > > + struct kvm_vcpu *owners[BITS_PER_LONG]; > > +}; > > +static DEFINE_PER_CPU(struct aia_hgei_control, aia_hgei); > > +static int hgei_parent_irq; > > + > > +unsigned int kvm_riscv_aia_nr_hgei; > > DEFINE_STATIC_KEY_FALSE(kvm_riscv_aia_available); > > > > +static int aia_find_hgei(struct kvm_vcpu *owner) > > +{ > > + int i, hgei; > > + unsigned long flags; > > + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); > > + > > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > > + > > + hgei = -1; > > + for (i = 1; i <= kvm_riscv_aia_nr_hgei; i++) { > > + if (hgctrl->owners[i] == owner) { > > + hgei = i; > > + break; > > + } > > + } > > + > > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > > + > > + return hgei; > > +} > > + > > static void aia_set_hvictl(bool ext_irq_pending) > > { > > unsigned long hvictl; > > @@ -55,6 +90,7 @@ void kvm_riscv_vcpu_aia_sync_interrupts(struct kvm_vcpu *vcpu) > > > > bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask) > > { > > + int hgei; > > unsigned long seip; > > > > if (!kvm_riscv_aia_available()) > > @@ -72,6 +108,10 @@ bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask) > > if (!kvm_riscv_aia_initialized(vcpu->kvm) || !seip) > > return false; > > > > + hgei = aia_find_hgei(vcpu); > > + if (hgei > 0) > > + return (csr_read(CSR_HGEIP) & BIT(hgei)) ? true : false; > > nit: return !!(csr_read(CSR_HGEIP) & BIT(hgei)) is a bit less verbose. Okay, I will update. > > > + > > return false; > > } > > > > @@ -343,6 +383,144 @@ int kvm_riscv_vcpu_aia_rmw_ireg(struct kvm_vcpu *vcpu, unsigned int csr_num, > > return KVM_INSN_EXIT_TO_USER_SPACE; > > } > > > > +int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner, > > + void __iomem **hgei_va, phys_addr_t *hgei_pa) > > +{ > > + int ret = -ENOENT; > > + unsigned long flags; > > + struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu); > > + > > + if (!kvm_riscv_aia_available()) > > + return -ENODEV; > > + if (!hgctrl) > > + return -ENODEV; > > nit: > > if (!kvm_riscv_aia_available() || !hgctrl) > return -ENODEV; Okay, I will update. > > > + > > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > > + > > + if (hgctrl->free_bitmap) { > > + ret = __ffs(hgctrl->free_bitmap); > > + hgctrl->free_bitmap &= ~BIT(ret); > > + hgctrl->owners[ret] = owner; > > + } > > + > > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > > + > > + /* TODO: To be updated later by AIA in-kernel irqchip support */ > > + if (hgei_va) > > + *hgei_va = NULL; > > + if (hgei_pa) > > + *hgei_pa = 0; > > + > > + return ret; > > +} > > + > > +void kvm_riscv_aia_free_hgei(int cpu, int hgei) > > +{ > > + unsigned long flags; > > + struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu); > > + > > + if (!kvm_riscv_aia_available() || !hgctrl) > > + return; > > + > > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > > + > > + if (hgei > 0 && hgei <= kvm_riscv_aia_nr_hgei) { > > + if (!(hgctrl->free_bitmap & BIT(hgei))) { > > + hgctrl->free_bitmap |= BIT(hgei); > > + hgctrl->owners[hgei] = NULL; > > + } > > + } > > + > > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > > +} > > + > > +void kvm_riscv_aia_wakeon_hgei(struct kvm_vcpu *owner, bool enable) > > +{ > > + int hgei; > > + > > + if (!kvm_riscv_aia_available()) > > + return; > > + > > + hgei = aia_find_hgei(owner); > > + if (hgei > 0) { > > + if (enable) > > + csr_set(CSR_HGEIE, BIT(hgei)); > > + else > > + csr_clear(CSR_HGEIE, BIT(hgei)); > > + } > > +} > > + > > +static irqreturn_t hgei_interrupt(int irq, void *dev_id) > > +{ > > + int i; > > + unsigned long hgei_mask, flags; > > + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); > > + > > + hgei_mask = csr_read(CSR_HGEIP) & csr_read(CSR_HGEIE); > > + csr_clear(CSR_HGEIE, hgei_mask); > > + > > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > > + > > + for_each_set_bit(i, &hgei_mask, BITS_PER_LONG) { > > + if (hgctrl->owners[i]) > > + kvm_vcpu_kick(hgctrl->owners[i]); > > + } > > + > > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > > + > > + return IRQ_HANDLED; > > +} > > + > > +static int aia_hgei_init(void) > > +{ > > + int cpu, 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; > > + } > > + > > + /* Find INTC irq domain */ > > + domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), > > + DOMAIN_BUS_ANY); > > + if (!domain) { > > + kvm_err("unable to find INTC domain\n"); > > + return -ENOENT; > > + } > > + > > + /* Map per-CPU SGEI interrupt from INTC domain */ > > + hgei_parent_irq = irq_create_mapping(domain, IRQ_S_GEXT); > > + if (!hgei_parent_irq) { > > + kvm_err("unable to map SGEI IRQ\n"); > > + return -ENOMEM; > > + } > > + > > + /* Request per-CPU SGEI interrupt */ > > + rc = request_percpu_irq(hgei_parent_irq, hgei_interrupt, > > + "riscv-kvm", &aia_hgei); > > + if (rc) { > > + kvm_err("failed to request SGEI IRQ\n"); > > + return rc; > > + } > > + > > + return 0; > > +} > > + > > +static void aia_hgei_exit(void) > > +{ > > + /* Free per-CPU SGEI interrupt */ > > + free_percpu_irq(hgei_parent_irq, &aia_hgei); > > +} > > + > > void kvm_riscv_aia_enable(void) > > { > > if (!kvm_riscv_aia_available()) > > @@ -357,21 +535,79 @@ void kvm_riscv_aia_enable(void) > > csr_write(CSR_HVIPRIO1H, 0x0); > > csr_write(CSR_HVIPRIO2H, 0x0); > > #endif > > + > > + /* Enable per-CPU SGEI interrupt */ > > + enable_percpu_irq(hgei_parent_irq, > > + irq_get_trigger_type(hgei_parent_irq)); > > + csr_set(CSR_HIE, BIT(IRQ_S_GEXT)); > > } > > > > void kvm_riscv_aia_disable(void) > > { > > + int i; > > + unsigned long flags; > > + struct kvm_vcpu *vcpu; > > + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); > > + > > if (!kvm_riscv_aia_available()) > > return; > > > > + /* Disable per-CPU SGEI interrupt */ > > + csr_clear(CSR_HIE, BIT(IRQ_S_GEXT)); > > + disable_percpu_irq(hgei_parent_irq); > > + > > aia_set_hvictl(false); > > + > > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > > + > > + for (i = 0; i <= kvm_riscv_aia_nr_hgei; i++) { > > I guess this should start at i = 1, but in this case it doesn't > matter since hgctrl->owners[0] should always be NULL. Yes, it doesn't matter in this case. > > > + vcpu = hgctrl->owners[i]; > > + if (!vcpu) > > + continue; > > + > > + /* > > + * We release hgctrl->lock before notifying IMSIC > > + * so that we don't have lock ordering issues. > > + */ > > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > > + > > + /* Notify IMSIC */ > > + kvm_riscv_vcpu_aia_imsic_release(vcpu); > > + > > + /* > > + * Wakeup VCPU if it was blocked so that it can > > + * run on other HARTs > > + */ > > + if (csr_read(CSR_HGEIE) & BIT(i)) { > > + csr_clear(CSR_HGEIE, BIT(i)); > > + kvm_vcpu_kick(vcpu); > > Doing all this outside the lock makes me wonder what happens when 'vcpu' > is no longer the owner at the time of kvm_riscv_vcpu_aia_imsic_release() > or kvm_vcpu_kick(). Even if the calls on the wrong vcpu are just noise, > then don't we still need to confirm that we release/kick the real owner > before we return from this function? > > It appears safe to call kvm_vcpu_kick() while holding the lock and > hgei_interrupt() does that. So, since there's currently no > implementation of kvm_riscv_vcpu_aia_imsic_release(), I'm not sure what > lock ordering issues we need to avoid. Next batch of AIA patches has kvm_riscv_vcpu_aia_imsic_release() where kvm_riscv_vcpu_aia_imsic_release() function will release the HGEI interrupt line. This is not to protect the kvm_vcpu_kick() call. Regards, Anup > > > + } > > + > > + raw_spin_lock_irqsave(&hgctrl->lock, flags); > > + } > > + > > + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); > > } > > > > int kvm_riscv_aia_init(void) > > { > > + int rc; > > + > > if (!riscv_isa_extension_available(NULL, SxAIA)) > > return -ENODEV; > > > > + /* Figure-out number of bits in HGEIE */ > > + csr_write(CSR_HGEIE, -1UL); > > + 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--; > > + > > + /* Initialize guest external interrupt line management */ > > + rc = aia_hgei_init(); > > + if (rc) > > + return rc; > > + > > /* Enable KVM AIA support */ > > static_branch_enable(&kvm_riscv_aia_available); > > > > @@ -380,4 +616,9 @@ int kvm_riscv_aia_init(void) > > > > void kvm_riscv_aia_exit(void) > > { > > + if (!kvm_riscv_aia_available()) > > + return; > > + > > + /* Cleanup the HGEI state */ > > + aia_hgei_exit(); > > } > > diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c > > index 6396352b4e4d..b0b46f48f31e 100644 > > --- a/arch/riscv/kvm/main.c > > +++ b/arch/riscv/kvm/main.c > > @@ -116,7 +116,8 @@ 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\n"); > > + kvm_info("AIA available with %d guest external interrupts\n", > > + kvm_riscv_aia_nr_hgei); > > > > rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE); > > if (rc) { > > diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c > > index 30acf3ebdc3d..eace51dd896f 100644 > > --- a/arch/riscv/kvm/vcpu.c > > +++ b/arch/riscv/kvm/vcpu.c > > @@ -249,10 +249,12 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) > > > > void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) > > { > > + kvm_riscv_aia_wakeon_hgei(vcpu, true); > > } > > > > void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) > > { > > + kvm_riscv_aia_wakeon_hgei(vcpu, false); > > } > > > > int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu) > > -- > > 2.34.1 > > > > Thanks, > drew
diff --git a/arch/riscv/include/asm/kvm_aia.h b/arch/riscv/include/asm/kvm_aia.h index 1de0717112e5..0938e0cadf80 100644 --- a/arch/riscv/include/asm/kvm_aia.h +++ b/arch/riscv/include/asm/kvm_aia.h @@ -44,10 +44,15 @@ struct kvm_vcpu_aia { #define irqchip_in_kernel(k) ((k)->arch.aia.in_kernel) +extern unsigned int kvm_riscv_aia_nr_hgei; DECLARE_STATIC_KEY_FALSE(kvm_riscv_aia_available); #define kvm_riscv_aia_available() \ static_branch_unlikely(&kvm_riscv_aia_available) +static inline void kvm_riscv_vcpu_aia_imsic_release(struct kvm_vcpu *vcpu) +{ +} + #define KVM_RISCV_AIA_IMSIC_TOPEI (ISELECT_MASK + 1) static inline int kvm_riscv_vcpu_aia_imsic_rmw(struct kvm_vcpu *vcpu, unsigned long isel, @@ -119,6 +124,11 @@ static inline void kvm_riscv_aia_destroy_vm(struct kvm *kvm) { } +int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner, + void __iomem **hgei_va, phys_addr_t *hgei_pa); +void kvm_riscv_aia_free_hgei(int cpu, int hgei); +void kvm_riscv_aia_wakeon_hgei(struct kvm_vcpu *owner, bool enable); + void kvm_riscv_aia_enable(void); void kvm_riscv_aia_disable(void); int kvm_riscv_aia_init(void); diff --git a/arch/riscv/kvm/aia.c b/arch/riscv/kvm/aia.c index d530912f28bc..1264783e7c4d 100644 --- a/arch/riscv/kvm/aia.c +++ b/arch/riscv/kvm/aia.c @@ -7,11 +7,46 @@ * Anup Patel <apatel@ventanamicro.com> */ +#include <linux/bitops.h> +#include <linux/irq.h> +#include <linux/irqdomain.h> #include <linux/kvm_host.h> +#include <linux/percpu.h> +#include <linux/spinlock.h> #include <asm/hwcap.h> +struct aia_hgei_control { + raw_spinlock_t lock; + unsigned long free_bitmap; + struct kvm_vcpu *owners[BITS_PER_LONG]; +}; +static DEFINE_PER_CPU(struct aia_hgei_control, aia_hgei); +static int hgei_parent_irq; + +unsigned int kvm_riscv_aia_nr_hgei; DEFINE_STATIC_KEY_FALSE(kvm_riscv_aia_available); +static int aia_find_hgei(struct kvm_vcpu *owner) +{ + int i, hgei; + unsigned long flags; + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); + + raw_spin_lock_irqsave(&hgctrl->lock, flags); + + hgei = -1; + for (i = 1; i <= kvm_riscv_aia_nr_hgei; i++) { + if (hgctrl->owners[i] == owner) { + hgei = i; + break; + } + } + + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); + + return hgei; +} + static void aia_set_hvictl(bool ext_irq_pending) { unsigned long hvictl; @@ -55,6 +90,7 @@ void kvm_riscv_vcpu_aia_sync_interrupts(struct kvm_vcpu *vcpu) bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask) { + int hgei; unsigned long seip; if (!kvm_riscv_aia_available()) @@ -72,6 +108,10 @@ bool kvm_riscv_vcpu_aia_has_interrupts(struct kvm_vcpu *vcpu, u64 mask) if (!kvm_riscv_aia_initialized(vcpu->kvm) || !seip) return false; + hgei = aia_find_hgei(vcpu); + if (hgei > 0) + return (csr_read(CSR_HGEIP) & BIT(hgei)) ? true : false; + return false; } @@ -343,6 +383,144 @@ int kvm_riscv_vcpu_aia_rmw_ireg(struct kvm_vcpu *vcpu, unsigned int csr_num, return KVM_INSN_EXIT_TO_USER_SPACE; } +int kvm_riscv_aia_alloc_hgei(int cpu, struct kvm_vcpu *owner, + void __iomem **hgei_va, phys_addr_t *hgei_pa) +{ + int ret = -ENOENT; + unsigned long flags; + struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu); + + if (!kvm_riscv_aia_available()) + return -ENODEV; + if (!hgctrl) + return -ENODEV; + + raw_spin_lock_irqsave(&hgctrl->lock, flags); + + if (hgctrl->free_bitmap) { + ret = __ffs(hgctrl->free_bitmap); + hgctrl->free_bitmap &= ~BIT(ret); + hgctrl->owners[ret] = owner; + } + + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); + + /* TODO: To be updated later by AIA in-kernel irqchip support */ + if (hgei_va) + *hgei_va = NULL; + if (hgei_pa) + *hgei_pa = 0; + + return ret; +} + +void kvm_riscv_aia_free_hgei(int cpu, int hgei) +{ + unsigned long flags; + struct aia_hgei_control *hgctrl = per_cpu_ptr(&aia_hgei, cpu); + + if (!kvm_riscv_aia_available() || !hgctrl) + return; + + raw_spin_lock_irqsave(&hgctrl->lock, flags); + + if (hgei > 0 && hgei <= kvm_riscv_aia_nr_hgei) { + if (!(hgctrl->free_bitmap & BIT(hgei))) { + hgctrl->free_bitmap |= BIT(hgei); + hgctrl->owners[hgei] = NULL; + } + } + + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); +} + +void kvm_riscv_aia_wakeon_hgei(struct kvm_vcpu *owner, bool enable) +{ + int hgei; + + if (!kvm_riscv_aia_available()) + return; + + hgei = aia_find_hgei(owner); + if (hgei > 0) { + if (enable) + csr_set(CSR_HGEIE, BIT(hgei)); + else + csr_clear(CSR_HGEIE, BIT(hgei)); + } +} + +static irqreturn_t hgei_interrupt(int irq, void *dev_id) +{ + int i; + unsigned long hgei_mask, flags; + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); + + hgei_mask = csr_read(CSR_HGEIP) & csr_read(CSR_HGEIE); + csr_clear(CSR_HGEIE, hgei_mask); + + raw_spin_lock_irqsave(&hgctrl->lock, flags); + + for_each_set_bit(i, &hgei_mask, BITS_PER_LONG) { + if (hgctrl->owners[i]) + kvm_vcpu_kick(hgctrl->owners[i]); + } + + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); + + return IRQ_HANDLED; +} + +static int aia_hgei_init(void) +{ + int cpu, 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; + } + + /* Find INTC irq domain */ + domain = irq_find_matching_fwnode(riscv_get_intc_hwnode(), + DOMAIN_BUS_ANY); + if (!domain) { + kvm_err("unable to find INTC domain\n"); + return -ENOENT; + } + + /* Map per-CPU SGEI interrupt from INTC domain */ + hgei_parent_irq = irq_create_mapping(domain, IRQ_S_GEXT); + if (!hgei_parent_irq) { + kvm_err("unable to map SGEI IRQ\n"); + return -ENOMEM; + } + + /* Request per-CPU SGEI interrupt */ + rc = request_percpu_irq(hgei_parent_irq, hgei_interrupt, + "riscv-kvm", &aia_hgei); + if (rc) { + kvm_err("failed to request SGEI IRQ\n"); + return rc; + } + + return 0; +} + +static void aia_hgei_exit(void) +{ + /* Free per-CPU SGEI interrupt */ + free_percpu_irq(hgei_parent_irq, &aia_hgei); +} + void kvm_riscv_aia_enable(void) { if (!kvm_riscv_aia_available()) @@ -357,21 +535,79 @@ void kvm_riscv_aia_enable(void) csr_write(CSR_HVIPRIO1H, 0x0); csr_write(CSR_HVIPRIO2H, 0x0); #endif + + /* Enable per-CPU SGEI interrupt */ + enable_percpu_irq(hgei_parent_irq, + irq_get_trigger_type(hgei_parent_irq)); + csr_set(CSR_HIE, BIT(IRQ_S_GEXT)); } void kvm_riscv_aia_disable(void) { + int i; + unsigned long flags; + struct kvm_vcpu *vcpu; + struct aia_hgei_control *hgctrl = this_cpu_ptr(&aia_hgei); + if (!kvm_riscv_aia_available()) return; + /* Disable per-CPU SGEI interrupt */ + csr_clear(CSR_HIE, BIT(IRQ_S_GEXT)); + disable_percpu_irq(hgei_parent_irq); + aia_set_hvictl(false); + + raw_spin_lock_irqsave(&hgctrl->lock, flags); + + for (i = 0; i <= kvm_riscv_aia_nr_hgei; i++) { + vcpu = hgctrl->owners[i]; + if (!vcpu) + continue; + + /* + * We release hgctrl->lock before notifying IMSIC + * so that we don't have lock ordering issues. + */ + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); + + /* Notify IMSIC */ + kvm_riscv_vcpu_aia_imsic_release(vcpu); + + /* + * Wakeup VCPU if it was blocked so that it can + * run on other HARTs + */ + if (csr_read(CSR_HGEIE) & BIT(i)) { + csr_clear(CSR_HGEIE, BIT(i)); + kvm_vcpu_kick(vcpu); + } + + raw_spin_lock_irqsave(&hgctrl->lock, flags); + } + + raw_spin_unlock_irqrestore(&hgctrl->lock, flags); } int kvm_riscv_aia_init(void) { + int rc; + if (!riscv_isa_extension_available(NULL, SxAIA)) return -ENODEV; + /* Figure-out number of bits in HGEIE */ + csr_write(CSR_HGEIE, -1UL); + 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--; + + /* Initialize guest external interrupt line management */ + rc = aia_hgei_init(); + if (rc) + return rc; + /* Enable KVM AIA support */ static_branch_enable(&kvm_riscv_aia_available); @@ -380,4 +616,9 @@ int kvm_riscv_aia_init(void) void kvm_riscv_aia_exit(void) { + if (!kvm_riscv_aia_available()) + return; + + /* Cleanup the HGEI state */ + aia_hgei_exit(); } diff --git a/arch/riscv/kvm/main.c b/arch/riscv/kvm/main.c index 6396352b4e4d..b0b46f48f31e 100644 --- a/arch/riscv/kvm/main.c +++ b/arch/riscv/kvm/main.c @@ -116,7 +116,8 @@ 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\n"); + kvm_info("AIA available with %d guest external interrupts\n", + kvm_riscv_aia_nr_hgei); rc = kvm_init(sizeof(struct kvm_vcpu), 0, THIS_MODULE); if (rc) { diff --git a/arch/riscv/kvm/vcpu.c b/arch/riscv/kvm/vcpu.c index 30acf3ebdc3d..eace51dd896f 100644 --- a/arch/riscv/kvm/vcpu.c +++ b/arch/riscv/kvm/vcpu.c @@ -249,10 +249,12 @@ int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu) void kvm_arch_vcpu_blocking(struct kvm_vcpu *vcpu) { + kvm_riscv_aia_wakeon_hgei(vcpu, true); } void kvm_arch_vcpu_unblocking(struct kvm_vcpu *vcpu) { + kvm_riscv_aia_wakeon_hgei(vcpu, false); } int kvm_arch_vcpu_runnable(struct kvm_vcpu *vcpu)
The RISC-V host will have one guest external interrupt line for each VS-level IMSICs associated with a HART. The guest external interrupt lines are per-HART resources and hypervisor can use HGEIE, HGEIP, and HIE CSRs to manage these guest external interrupt lines. Signed-off-by: Anup Patel <apatel@ventanamicro.com> --- arch/riscv/include/asm/kvm_aia.h | 10 ++ arch/riscv/kvm/aia.c | 241 +++++++++++++++++++++++++++++++ arch/riscv/kvm/main.c | 3 +- arch/riscv/kvm/vcpu.c | 2 + 4 files changed, 255 insertions(+), 1 deletion(-)