On Mon, Nov 20 2023 at 16:28, gregkh@linuxfoundation.org wrote:
The patch below does not apply to the 6.1-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to stable@vger.kernel.org.
See below.
Thanks,
tglx --- From: Koichiro Den den@valinux.co.jp Date: Thu Oct 26 12:20:36 2023 +0900 Subject: x86/apic/msi: Fix misconfigured non-maskable MSI quirk
commit b56ebe7c896dc78b5865ec2c4b1dae3c93537517 upstream.
commit ef8dd01538ea ("genirq/msi: Make interrupt allocation less convoluted"), reworked the code so that the x86 specific quirk for affinity setting of non-maskable PCI/MSI interrupts is not longer activated if necessary.
This could be solved by restoring the original logic in the core MSI code, but after a deeper analysis it turned out that the quirk flag is not required at all.
The quirk is only required when the PCI/MSI device cannot mask the MSI interrupts, which in turn also prevents reservation mode from being enabled for the affected interrupt.
This allows ot remove the NOMASK quirk bit completely as msi_set_affinity() can instead check whether reservation mode is enabled for the interrupt, which gives exactly the same answer.
Even in the momentary non-existing case that the reservation mode would be not set for a maskable MSI interrupt this would not cause any harm as it just would cause msi_set_affinity() to go needlessly through the functionaly equivalent slow path, which works perfectly fine with maskable interrupts as well.
Rework msi_set_affinity() to query the reservation mode and remove all NOMASK quirk logic from the core code.
[ tglx: Massaged changelog ]
Fixes: ef8dd01538ea ("genirq/msi: Make interrupt allocation less convoluted") Suggested-by: Thomas Gleixner tglx@linutronix.de Signed-off-by: Koichiro Den den@valinux.co.jp Signed-off-by: Thomas Gleixner tglx@linutronix.de Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20231026032036.2462428-1-den@valinux.co.jp --- arch/x86/kernel/apic/msi.c | 8 +++----- include/linux/irq.h | 24 +++--------------------- kernel/irq/debugfs.c | 1 - kernel/irq/msi.c | 12 +----------- 4 files changed, 7 insertions(+), 38 deletions(-)
--- a/arch/x86/kernel/apic/msi.c +++ b/arch/x86/kernel/apic/msi.c @@ -55,14 +55,14 @@ msi_set_affinity(struct irq_data *irqd, * caused by the non-atomic update of the address/data pair. * * Direct update is possible when: - * - The MSI is maskable (remapped MSI does not use this code path)). - * The quirk bit is not set in this case. + * - The MSI is maskable (remapped MSI does not use this code path). + * The reservation mode bit is set in this case. * - The new vector is the same as the old vector * - The old vector is MANAGED_IRQ_SHUTDOWN_VECTOR (interrupt starts up) * - The interrupt is not yet started up * - The new destination CPU is the same as the old destination CPU */ - if (!irqd_msi_nomask_quirk(irqd) || + if (!irqd_can_reserve(irqd) || cfg->vector == old_cfg.vector || old_cfg.vector == MANAGED_IRQ_SHUTDOWN_VECTOR || !irqd_is_started(irqd) || @@ -202,8 +202,6 @@ struct irq_domain * __init native_create if (!d) { irq_domain_free_fwnode(fn); pr_warn("Failed to initialize PCI-MSI irqdomain.\n"); - } else { - d->flags |= IRQ_DOMAIN_MSI_NOMASK_QUIRK; } return d; } --- a/include/linux/irq.h +++ b/include/linux/irq.h @@ -215,8 +215,6 @@ struct irq_data { * IRQD_SINGLE_TARGET - IRQ allows only a single affinity target * IRQD_DEFAULT_TRIGGER_SET - Expected trigger already been set * IRQD_CAN_RESERVE - Can use reservation mode - * IRQD_MSI_NOMASK_QUIRK - Non-maskable MSI quirk for affinity change - * required * IRQD_HANDLE_ENFORCE_IRQCTX - Enforce that handle_irq_*() is only invoked * from actual interrupt context. * IRQD_AFFINITY_ON_ACTIVATE - Affinity is set on activation. Don't call @@ -245,10 +243,9 @@ enum { IRQD_SINGLE_TARGET = (1 << 24), IRQD_DEFAULT_TRIGGER_SET = (1 << 25), IRQD_CAN_RESERVE = (1 << 26), - IRQD_MSI_NOMASK_QUIRK = (1 << 27), - IRQD_HANDLE_ENFORCE_IRQCTX = (1 << 28), - IRQD_AFFINITY_ON_ACTIVATE = (1 << 29), - IRQD_IRQ_ENABLED_ON_SUSPEND = (1 << 30), + IRQD_HANDLE_ENFORCE_IRQCTX = (1 << 27), + IRQD_AFFINITY_ON_ACTIVATE = (1 << 28), + IRQD_IRQ_ENABLED_ON_SUSPEND = (1 << 29), };
#define __irqd_to_state(d) ACCESS_PRIVATE((d)->common, state_use_accessors) @@ -423,21 +420,6 @@ static inline bool irqd_can_reserve(stru return __irqd_to_state(d) & IRQD_CAN_RESERVE; }
-static inline void irqd_set_msi_nomask_quirk(struct irq_data *d) -{ - __irqd_to_state(d) |= IRQD_MSI_NOMASK_QUIRK; -} - -static inline void irqd_clr_msi_nomask_quirk(struct irq_data *d) -{ - __irqd_to_state(d) &= ~IRQD_MSI_NOMASK_QUIRK; -} - -static inline bool irqd_msi_nomask_quirk(struct irq_data *d) -{ - return __irqd_to_state(d) & IRQD_MSI_NOMASK_QUIRK; -} - static inline void irqd_set_affinity_on_activate(struct irq_data *d) { __irqd_to_state(d) |= IRQD_AFFINITY_ON_ACTIVATE; --- a/kernel/irq/debugfs.c +++ b/kernel/irq/debugfs.c @@ -121,7 +121,6 @@ static const struct irq_bit_descr irqdat BIT_MASK_DESCR(IRQD_AFFINITY_ON_ACTIVATE), BIT_MASK_DESCR(IRQD_MANAGED_SHUTDOWN), BIT_MASK_DESCR(IRQD_CAN_RESERVE), - BIT_MASK_DESCR(IRQD_MSI_NOMASK_QUIRK),
BIT_MASK_DESCR(IRQD_FORWARDED_TO_VCPU),
--- a/kernel/irq/msi.c +++ b/kernel/irq/msi.c @@ -807,7 +807,6 @@ static int msi_handle_pci_fail(struct ir
#define VIRQ_CAN_RESERVE 0x01 #define VIRQ_ACTIVATE 0x02 -#define VIRQ_NOMASK_QUIRK 0x04
static int msi_init_virq(struct irq_domain *domain, int virq, unsigned int vflags) { @@ -816,8 +815,6 @@ static int msi_init_virq(struct irq_doma
if (!(vflags & VIRQ_CAN_RESERVE)) { irqd_clr_can_reserve(irqd); - if (vflags & VIRQ_NOMASK_QUIRK) - irqd_set_msi_nomask_quirk(irqd);
/* * If the interrupt is managed but no CPU is available to @@ -877,15 +874,8 @@ int __msi_domain_alloc_irqs(struct irq_d * Interrupt can use a reserved vector and will not occupy * a real device vector until the interrupt is requested. */ - if (msi_check_reservation_mode(domain, info, dev)) { + if (msi_check_reservation_mode(domain, info, dev)) vflags |= VIRQ_CAN_RESERVE; - /* - * MSI affinity setting requires a special quirk (X86) when - * reservation mode is active. - */ - if (domain->flags & IRQ_DOMAIN_MSI_NOMASK_QUIRK) - vflags |= VIRQ_NOMASK_QUIRK; - }
msi_for_each_desc(desc, dev, MSI_DESC_NOTASSOCIATED) { ops->set_desc(&arg, desc);