From: Quan Xu <quan.xu@intel.com>
To: xen-devel@lists.xen.org
Cc: Dario Faggioli <dario.faggioli@citrix.com>,
Jan Beulich <jbeulich@suse.com>,
Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>,
Quan Xu <quan.xu@intel.com>
Subject: [PATCH v3 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization
Date: Wed, 9 Mar 2016 21:17:34 +0800 [thread overview]
Message-ID: <1457529455-38314-2-git-send-email-quan.xu@intel.com> (raw)
In-Reply-To: <1457529455-38314-1-git-send-email-quan.xu@intel.com>
pcidevs_lock should be held with interrupt enabled. However there remains
an exception in AMD IOMMU code, where the lock is acquired with interrupt
disabled. This inconsistency might lead to deadlock.
The fix is straightforward to use spin_lock instead. Also interrupt has been
enabled when this function is invoked, so we're sure consistency around
pcidevs_lock can be guaranteed after this fix.
Signed-off-by: Quan Xu <quan.xu@intel.com>
Reviewed-by: Dario Faggioli <dario.faggioli@citrix.com>
CC: Suravee Suthikulpanit <suravee.suthikulpanit@amd.com>
CC: Dario Faggioli <dario.faggioli@citrix.com>
CC: Jan Beulich <jbeulich@suse.com>
---
xen/drivers/passthrough/amd/iommu_init.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/xen/drivers/passthrough/amd/iommu_init.c b/xen/drivers/passthrough/amd/iommu_init.c
index d90a2d2..a400497 100644
--- a/xen/drivers/passthrough/amd/iommu_init.c
+++ b/xen/drivers/passthrough/amd/iommu_init.c
@@ -778,7 +778,6 @@ static bool_t __init set_iommu_interrupt_handler(struct amd_iommu *iommu)
{
int irq, ret;
hw_irq_controller *handler;
- unsigned long flags;
u16 control;
irq = create_irq(NUMA_NO_NODE);
@@ -788,10 +787,10 @@ static bool_t __init set_iommu_interrupt_handler(struct amd_iommu *iommu)
return 0;
}
- spin_lock_irqsave(&pcidevs_lock, flags);
+ spin_lock(&pcidevs_lock);
iommu->msi.dev = pci_get_pdev(iommu->seg, PCI_BUS(iommu->bdf),
PCI_DEVFN2(iommu->bdf));
- spin_unlock_irqrestore(&pcidevs_lock, flags);
+ spin_unlock(&pcidevs_lock);
if ( !iommu->msi.dev )
{
AMD_IOMMU_DEBUG("IOMMU: no pdev for %04x:%02x:%02x.%u\n",
--
1.9.1
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next prev parent reply other threads:[~2016-03-09 13:17 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-09 13:17 [PATCH v3 0/2] Make the pcidevs_lock a recursive one Quan Xu
2016-03-09 13:17 ` Quan Xu [this message]
2016-03-09 14:59 ` [PATCH v3 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization Dario Faggioli
2016-03-10 6:12 ` Xu, Quan
2016-03-11 3:24 ` Meng Xu
2016-03-11 6:54 ` Xu, Quan
2016-03-11 10:35 ` Dario Faggioli
2016-03-11 12:36 ` Xu, Quan
2016-03-11 13:58 ` Dario Faggioli
2016-03-11 14:49 ` Meng Xu
2016-03-11 15:55 ` Dario Faggioli
2016-03-11 17:17 ` Meng Xu
2016-03-11 14:41 ` Meng Xu
2016-03-11 16:12 ` Dario Faggioli
2016-03-09 13:17 ` [PATCH v3 2/2] IOMMU/spinlock: Make the pcidevs_lock a recursive one Quan Xu
2016-03-09 17:45 ` Dario Faggioli
2016-03-10 1:21 ` Xu, Quan
2016-03-10 9:52 ` Jan Beulich
2016-03-10 11:27 ` Xu, Quan
2016-03-10 13:06 ` Jan Beulich
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