diff options
| author | Sean Christopherson <seanjc@google.com> | 2025-04-01 09:34:40 -0700 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2025-04-24 11:19:37 -0700 |
| commit | 600e9606046ac3b9b7a3f0500d08a179df84c45e (patch) | |
| tree | 59fb06558b441845233273d6e0dfd22478c5da7a | |
| parent | 45eb29140e68ffe8e93a5471006858a018480a45 (diff) | |
x86/irq: Ensure initial PIR loads are performed exactly once
Ensure the PIR is read exactly once at the start of handle_pending_pir(),
to guarantee that checking for an outstanding posted interrupt in a given
chuck doesn't reload the chunk from the "real" PIR. Functionally, a reload
is benign, but it would defeat the purpose of pre-loading into a copy.
Fixes: 1b03d82ba15e ("x86/irq: Install posted MSI notification handler")
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/r/20250401163447.846608-2-seanjc@google.com
Signed-off-by: Sean Christopherson <seanjc@google.com>
| -rw-r--r-- | arch/x86/kernel/irq.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/x86/kernel/irq.c b/arch/x86/kernel/irq.c index 81f9b78e0f7b..6cd5d2d6c58a 100644 --- a/arch/x86/kernel/irq.c +++ b/arch/x86/kernel/irq.c @@ -419,7 +419,7 @@ static __always_inline bool handle_pending_pir(u64 *pir, struct pt_regs *regs) bool handled = false; for (i = 0; i < 4; i++) - pir_copy[i] = pir[i]; + pir_copy[i] = READ_ONCE(pir[i]); for (i = 0; i < 4; i++) { if (!pir_copy[i]) |