From 6fa25d568f4e597b1940309d97cfd98f4f6eecd6 Mon Sep 17 00:00:00 2001 From: Roger Pau Monne Date: Wed, 10 Jun 2020 16:29:22 +0200 Subject: [PATCH] x86/passthrough: do not assert edge triggered GSIs for PVH dom0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Edge triggered interrupts do not assert the line, so the handling done in Xen should also avoid asserting it. Asserting the line prevents further edge triggered interrupts on the same vIO-APIC pin from being delivered, since the line is not de-asserted. One case of such kind of interrupt is the RTC timer, which is edge triggered and available to a PVH dom0. Note this should not affect domUs, as it only modifies the behavior of IDENTITY_GSI kind of passed through interrupts. Signed-off-by: Roger Pau Monné Acked-by: Andrew Cooper Reviewed-by: Paul Durrant Release-acked-by: Paul Durrant --- xen/arch/x86/hvm/irq.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/xen/arch/x86/hvm/irq.c b/xen/arch/x86/hvm/irq.c index 9c8adbc495..fd02cf2e8d 100644 --- a/xen/arch/x86/hvm/irq.c +++ b/xen/arch/x86/hvm/irq.c @@ -169,9 +169,10 @@ void hvm_pci_intx_deassert( void hvm_gsi_assert(struct domain *d, unsigned int gsi) { + int trig = vioapic_get_trigger_mode(d, gsi); struct hvm_irq *hvm_irq = hvm_domain_irq(d); - if ( gsi >= hvm_irq->nr_gsis ) + if ( gsi >= hvm_irq->nr_gsis || trig < 0 ) { ASSERT_UNREACHABLE(); return; @@ -186,9 +187,10 @@ void hvm_gsi_assert(struct domain *d, unsigned int gsi) * to know if the GSI is pending or not. */ spin_lock(&d->arch.hvm.irq_lock); - if ( !hvm_irq->gsi_assert_count[gsi] ) + if ( trig == VIOAPIC_EDGE_TRIG || !hvm_irq->gsi_assert_count[gsi] ) { - hvm_irq->gsi_assert_count[gsi] = 1; + if ( trig == VIOAPIC_LEVEL_TRIG ) + hvm_irq->gsi_assert_count[gsi] = 1; assert_gsi(d, gsi); } spin_unlock(&d->arch.hvm.irq_lock); @@ -196,11 +198,12 @@ void hvm_gsi_assert(struct domain *d, unsigned int gsi) void hvm_gsi_deassert(struct domain *d, unsigned int gsi) { + int trig = vioapic_get_trigger_mode(d, gsi); struct hvm_irq *hvm_irq = hvm_domain_irq(d); - if ( gsi >= hvm_irq->nr_gsis ) + if ( trig <= VIOAPIC_EDGE_TRIG || gsi >= hvm_irq->nr_gsis ) { - ASSERT_UNREACHABLE(); + ASSERT(trig == VIOAPIC_EDGE_TRIG && gsi < hvm_irq->nr_gsis); return; } -- 2.30.2