On Tue, 16 Nov 2021 14:40:22 +0100 Cédric Le Goater clg@kaod.org wrote:
Commit 4f86a06e2d6e ("irqdomain: Make normal and nomap irqdomains exclusive") introduced an IRQ_DOMAIN_FLAG_NO_MAP flag to isolate the 'nomap' domains still in use under the powerpc arch. With this new flag, the revmap_tree of the IRQ domain is not used anymore. This change broke the support of shared LSIs [1] in the XIVE driver because it was relying on a lookup in the revmap_tree to query previously mapped interrupts. Linux now creates two distinct IRQ mappings on the same HW IRQ which can lead to unexpected behavior in the drivers.
The XIVE IRQ domain is not a direct mapping domain and its HW IRQ interrupt number space is rather large : 1M/socket on POWER9 and POWER10, change the XIVE driver to use a 'tree' domain type instead.
[1] For instance, a linux KVM guest with virtio-rng and virtio-balloon devices.
Cc: Marc Zyngier maz@kernel.org Cc: stable@vger.kernel.org # v5.14+ Fixes: 4f86a06e2d6e ("irqdomain: Make normal and nomap irqdomains exclusive") Signed-off-by: Cédric Le Goater clg@kaod.org
Tested-by: Greg Kurz groug@kaod.org
with a KVM guest + virtio-rng + virtio-balloon on a POWER9 host.
Marc,
The Fixes tag is there because the patch in question revealed that something was broken in XIVE. genirq is not in cause. However, I don't know for PS3 and Cell. May be less critical for now. arch/powerpc/sysdev/xive/common.c | 3 +-- arch/powerpc/sysdev/xive/Kconfig | 1 - 2 files changed, 1 insertion(+), 3 deletions(-)
diff --git a/arch/powerpc/sysdev/xive/common.c b/arch/powerpc/sysdev/xive/common.c index fed6fd16c8f4..9d0f0fe25598 100644 --- a/arch/powerpc/sysdev/xive/common.c +++ b/arch/powerpc/sysdev/xive/common.c @@ -1536,8 +1536,7 @@ static const struct irq_domain_ops xive_irq_domain_ops = { static void __init xive_init_host(struct device_node *np) {
- xive_irq_domain = irq_domain_add_nomap(np, XIVE_MAX_IRQ,
&xive_irq_domain_ops, NULL);
- xive_irq_domain = irq_domain_add_tree(np, &xive_irq_domain_ops, NULL); if (WARN_ON(xive_irq_domain == NULL)) return; irq_set_default_host(xive_irq_domain);
diff --git a/arch/powerpc/sysdev/xive/Kconfig b/arch/powerpc/sysdev/xive/Kconfig index 97796c6b63f0..785c292d104b 100644 --- a/arch/powerpc/sysdev/xive/Kconfig +++ b/arch/powerpc/sysdev/xive/Kconfig @@ -3,7 +3,6 @@ config PPC_XIVE bool select PPC_SMP_MUXED_IPI select HARDIRQS_SW_RESEND
- select IRQ_DOMAIN_NOMAP
config PPC_XIVE_NATIVE bool