From 8c97eb6551f2942a634483ecefdf0e7978ae50e1 Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Thu, 22 Mar 2018 14:59:00 +0100 Subject: [PATCH] x86/pt: mask MSI vectors on unbind MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit When a MSI device with per-vector masking capabilities is detected or added to Xen all the vectors are masked when initializing it. This implies that the first time the interrupt is bound to a domain it's masked. This however only applies to the first time the interrupt is bound because neither the unbind nor the pirq unmap will mask the vector again. In order to fix this re-mask the interrupt when unbinding it from a guest. This makes sure that pairs of bind/unbind will always get the same masking state. Note that no issues have been reported regarding this behavior because QEMU always uses the newly introduced XEN_PT_GFLAGSSHIFT_UNMASKED when binding interrupts, so it's always unmasked. Signed-off-by: Roger Pau Monné Reviewed-by: Jan Beulich --- xen/drivers/passthrough/io.c | 15 +++++++++++++++ 1 file changed, 15 insertions(+) diff --git a/xen/drivers/passthrough/io.c b/xen/drivers/passthrough/io.c index 8f16e6c0a5..bab3aa349a 100644 --- a/xen/drivers/passthrough/io.c +++ b/xen/drivers/passthrough/io.c @@ -645,7 +645,22 @@ int pt_irq_destroy_bind( } break; case PT_IRQ_TYPE_MSI: + { + unsigned long flags; + struct irq_desc *desc = domain_spin_lock_irq_desc(d, machine_gsi, + &flags); + + if ( !desc ) + return -EINVAL; + /* + * Leave the MSI masked, so that the state when calling + * pt_irq_create_bind is consistent across bind/unbinds. + */ + guest_mask_msi_irq(desc, true); + spin_unlock_irqrestore(&desc->lock, flags); break; + } + default: return -EOPNOTSUPP; } -- 2.30.2