diff options
| author | Andrew Jones <andrew.jones@oss.qualcomm.com> | 2026-09-25 17:51:16 +0200 |
|---|---|---|
| committer | Anup Patel <anup@brainfault.org> | 2026-10-22 10:40:16 +0530 |
| commit | 80f6e72b21aa773e71c748e1e5a6d3aa8d458bd7 (patch) | |
| tree | 99ec52f27810fac0b81695fb50e1fd5941a7f379 /arch/riscv | |
| parent | bae99073549aba7c3d79685a4640a46aa5c55340 (diff) | |
RISC-V: KVM: Use a raw lock for IMSIC wakeup state
kvm_riscv_vcpu_aia_imsic_put() can run from the scheduler preemption
notifier while the raw runqueue lock is held. Taking vsfile_lock, an
rwlock_t, there violates the lockdep wait-context rules.
Protect the CPU/HGEI pair with a separate raw spinlock. All updates to
that pair retain vsfile_lock and take the new lock, while scheduler-out
uses only the new lock around the HGEIE update. This keeps the wakeup
setup serialized with VS-file publication and release without bringing
wider IMSIC operations into a raw critical section.
Fixes: 4cec89db80ba ("RISC-V: KVM: Move HGEI[E|P] CSR access to IMSIC virtualization")
Signed-off-by: Andrew Jones <andrew.jones@oss.qualcomm.com>
Reviewed-by: Anup Patel <anup@brainfault.org>
Link: https://lore.kernel.org/r/20260925155116.465203-1-andrew.jones@oss.qualcomm.com
Signed-off-by: Anup Patel <anup@brainfault.org>
Diffstat (limited to 'arch/riscv')
| -rw-r--r-- | arch/riscv/kvm/aia_imsic.c | 25 |
1 files changed, 19 insertions, 6 deletions
diff --git a/arch/riscv/kvm/aia_imsic.c b/arch/riscv/kvm/aia_imsic.c index 984b2212328a..302938972aa0 100644 --- a/arch/riscv/kvm/aia_imsic.c +++ b/arch/riscv/kvm/aia_imsic.c @@ -48,6 +48,8 @@ struct imsic { /* IMSIC VS-file */ rwlock_t vsfile_lock; + /* Writers hold both locks; scheduler-out only takes vsfile_hgei_lock. */ + raw_spinlock_t vsfile_hgei_lock; int vsfile_cpu; int vsfile_hgei; void __iomem *vsfile_va; @@ -488,6 +490,17 @@ static void imsic_vsfile_local_update(int vsfile_hgei, u32 nr_eix, csr_write(CSR_VSISELECT, old_vsiselect); } +static void imsic_vsfile_set_hgei(struct imsic *imsic, int cpu, int hgei) +{ + unsigned long flags; + + /* Serialize the CPU/HGEI pair with scheduler-out's wakeup setup. */ + raw_spin_lock_irqsave(&imsic->vsfile_hgei_lock, flags); + imsic->vsfile_cpu = cpu; + imsic->vsfile_hgei = hgei; + raw_spin_unlock_irqrestore(&imsic->vsfile_hgei_lock, flags); +} + static void imsic_vsfile_cleanup(struct imsic *imsic) { int old_vsfile_hgei, old_vsfile_cpu; @@ -502,7 +515,7 @@ static void imsic_vsfile_cleanup(struct imsic *imsic) write_lock_irqsave(&imsic->vsfile_lock, flags); old_vsfile_hgei = imsic->vsfile_hgei; old_vsfile_cpu = imsic->vsfile_cpu; - imsic->vsfile_cpu = imsic->vsfile_hgei = -1; + imsic_vsfile_set_hgei(imsic, -1, -1); imsic->vsfile_va = NULL; imsic->vsfile_pa = 0; write_unlock_irqrestore(&imsic->vsfile_lock, flags); @@ -633,10 +646,10 @@ void kvm_riscv_vcpu_aia_imsic_put(struct kvm_vcpu *vcpu) if (!kvm_vcpu_is_blocking(vcpu)) return; - read_lock_irqsave(&imsic->vsfile_lock, flags); + raw_spin_lock_irqsave(&imsic->vsfile_hgei_lock, flags); if (imsic->vsfile_cpu > -1) csr_set(CSR_HGEIE, BIT(imsic->vsfile_hgei)); - read_unlock_irqrestore(&imsic->vsfile_lock, flags); + raw_spin_unlock_irqrestore(&imsic->vsfile_hgei_lock, flags); } void kvm_riscv_vcpu_aia_imsic_release(struct kvm_vcpu *vcpu) @@ -653,7 +666,7 @@ void kvm_riscv_vcpu_aia_imsic_release(struct kvm_vcpu *vcpu) write_lock_irqsave(&imsic->vsfile_lock, flags); old_vsfile_hgei = imsic->vsfile_hgei; old_vsfile_cpu = imsic->vsfile_cpu; - imsic->vsfile_cpu = imsic->vsfile_hgei = -1; + imsic_vsfile_set_hgei(imsic, -1, -1); imsic->vsfile_va = NULL; imsic->vsfile_pa = 0; write_unlock_irqrestore(&imsic->vsfile_lock, flags); @@ -767,8 +780,7 @@ int kvm_riscv_vcpu_aia_imsic_update(struct kvm_vcpu *vcpu) /* Update new IMSIC VS-file details in IMSIC context */ write_lock_irqsave(&imsic->vsfile_lock, flags); - imsic->vsfile_hgei = new_vsfile_hgei; - imsic->vsfile_cpu = vcpu->cpu; + imsic_vsfile_set_hgei(imsic, vcpu->cpu, new_vsfile_hgei); imsic->vsfile_va = new_vsfile_va; imsic->vsfile_pa = new_vsfile_pa; write_unlock_irqrestore(&imsic->vsfile_lock, flags); @@ -1025,6 +1037,7 @@ int kvm_riscv_vcpu_aia_imsic_init(struct kvm_vcpu *vcpu) /* Setup IMSIC context */ imsic->nr_msis = kvm->arch.aia.nr_ids + 1; rwlock_init(&imsic->vsfile_lock); + raw_spin_lock_init(&imsic->vsfile_hgei_lock); imsic->nr_eix = BITS_TO_U64(imsic->nr_msis); imsic->nr_hw_eix = BITS_TO_U64(kvm_riscv_aia_max_ids); imsic->vsfile_hgei = imsic->vsfile_cpu = -1; |