From: Quan Xu <quan.xu@intel.com>
To: xen-devel@lists.xen.org
Cc: Kevin Tian <kevin.tian@intel.com>,
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 v4 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization
Date: Thu, 10 Mar 2016 22:10:06 +0800 [thread overview]
Message-ID: <1457619007-41460-2-git-send-email-quan.xu@intel.com> (raw)
In-Reply-To: <1457619007-41460-1-git-send-email-quan.xu@intel.com>
pcidevs_lock doesn't require interrupts to be disabled while being acquired.
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>
CC: Kevin Tian <kevin.tian@intel.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:[~2016-03-10 14:10 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-03-10 14:10 [PATCH v4 0/2] Make the pcidevs_lock a recursive one Quan Xu
2016-03-10 14:10 ` Quan Xu [this message]
2016-03-11 0:24 ` [PATCH v4 1/2] IOMMU/spinlock: Fix a bug found in AMD IOMMU initialization Tian, Kevin
2016-03-11 1:40 ` Xu, Quan
2016-03-10 14:10 ` [PATCH v4 2/2] IOMMU/spinlock: Make the pcidevs_lock a recursive one Quan Xu
2016-03-10 14:32 ` Jan Beulich
2016-03-10 14:38 ` Dario Faggioli
2016-03-11 1:38 ` Xu, Quan
2016-03-11 1:33 ` Xu, Quan
2016-03-16 2:39 ` [PATCH v4 0/2] " Xu, Quan
2016-03-16 8:39 ` Dario Faggioli
2016-03-16 10:45 ` Jan Beulich
2016-03-17 1:39 ` Xu, Quan
2016-03-17 2:07 ` Dario Faggioli
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