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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [xen-unstable] IOMMU: don't immediately disable bus mastering on faults
# HG changeset patch
# User Jan Beulich <jbeulich@xxxxxxxx>
# Date 1352709367 -3600
# Node ID fdb69dd527cd01a46f87efb380050559dcf12d37
# Parent 286ef4ced2164f4e9bf52fd0c52248182e69a6e6
IOMMU: don't immediately disable bus mastering on faults
Instead, give the owning domain at least a small opportunity of fixing
things up, and allow for rare faults to not bring down the device at
all.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Acked-by: Tim Deegan <tim@xxxxxxx>
Acked-by: Dario Faggioli <dario.faggioli@xxxxxxxxxx>
---
diff -r 286ef4ced216 -r fdb69dd527cd xen/drivers/passthrough/amd/iommu_init.c
--- a/xen/drivers/passthrough/amd/iommu_init.c Mon Nov 12 09:34:57 2012 +0100
+++ b/xen/drivers/passthrough/amd/iommu_init.c Mon Nov 12 09:36:07 2012 +0100
@@ -566,7 +566,7 @@ static hw_irq_controller iommu_maskable_
static void parse_event_log_entry(struct amd_iommu *iommu, u32 entry[])
{
- u16 domain_id, device_id, bdf, cword, flags;
+ u16 domain_id, device_id, bdf, flags;
u32 code;
u64 *addr;
int count = 0;
@@ -620,18 +620,10 @@ static void parse_event_log_entry(struct
"fault address = %#"PRIx64", flags = %#x\n",
event_str[code-1], domain_id, device_id, *addr, flags);
- /* Tell the device to stop DMAing; we can't rely on the guest to
- * control it for us. */
for ( bdf = 0; bdf < ivrs_bdf_entries; bdf++ )
if ( get_dma_requestor_id(iommu->seg, bdf) == device_id )
- {
- cword = pci_conf_read16(iommu->seg, PCI_BUS(bdf),
- PCI_SLOT(bdf), PCI_FUNC(bdf),
- PCI_COMMAND);
- pci_conf_write16(iommu->seg, PCI_BUS(bdf), PCI_SLOT(bdf),
- PCI_FUNC(bdf), PCI_COMMAND,
- cword & ~PCI_COMMAND_MASTER);
- }
+ pci_check_disable_device(iommu->seg, PCI_BUS(bdf),
+ PCI_DEVFN2(bdf));
}
else
{
diff -r 286ef4ced216 -r fdb69dd527cd xen/drivers/passthrough/iommu.c
--- a/xen/drivers/passthrough/iommu.c Mon Nov 12 09:34:57 2012 +0100
+++ b/xen/drivers/passthrough/iommu.c Mon Nov 12 09:36:07 2012 +0100
@@ -215,6 +215,7 @@ static int device_assigned(u16 seg, u8 b
static int assign_device(struct domain *d, u16 seg, u8 bus, u8 devfn)
{
struct hvm_iommu *hd = domain_hvm_iommu(d);
+ struct pci_dev *pdev;
int rc = 0;
if ( !iommu_enabled || !hd->platform_ops )
@@ -228,6 +229,10 @@ static int assign_device(struct domain *
return -EXDEV;
spin_lock(&pcidevs_lock);
+ pdev = pci_get_pdev(seg, bus, devfn);
+ if ( pdev )
+ pdev->fault.count = 0;
+
if ( (rc = hd->platform_ops->assign_device(d, seg, bus, devfn)) )
goto done;
@@ -379,6 +384,8 @@ int deassign_device(struct domain *d, u1
return ret;
}
+ pdev->fault.count = 0;
+
if ( !has_arch_pdevs(d) && need_iommu(d) )
{
d->need_iommu = 0;
diff -r 286ef4ced216 -r fdb69dd527cd xen/drivers/passthrough/pci.c
--- a/xen/drivers/passthrough/pci.c Mon Nov 12 09:34:57 2012 +0100
+++ b/xen/drivers/passthrough/pci.c Mon Nov 12 09:36:07 2012 +0100
@@ -672,6 +672,36 @@ int __init pci_device_detect(u16 seg, u8
return 1;
}
+void pci_check_disable_device(u16 seg, u8 bus, u8 devfn)
+{
+ struct pci_dev *pdev;
+ s_time_t now = NOW();
+ u16 cword;
+
+ spin_lock(&pcidevs_lock);
+ pdev = pci_get_pdev(seg, bus, devfn);
+ if ( pdev )
+ {
+ if ( now < pdev->fault.time ||
+ now - pdev->fault.time > MILLISECS(10) )
+ pdev->fault.count >>= 1;
+ pdev->fault.time = now;
+ if ( ++pdev->fault.count < PT_FAULT_THRESHOLD )
+ pdev = NULL;
+ }
+ spin_unlock(&pcidevs_lock);
+
+ if ( !pdev )
+ return;
+
+ /* Tell the device to stop DMAing; we can't rely on the guest to
+ * control it for us. */
+ cword = pci_conf_read16(seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+ PCI_COMMAND);
+ pci_conf_write16(seg, bus, PCI_SLOT(devfn), PCI_FUNC(devfn),
+ PCI_COMMAND, cword & ~PCI_COMMAND_MASTER);
+}
+
/*
* scan pci devices to add all existed PCI devices to alldevs_list,
* and setup pci hierarchy in array bus2bridge.
diff -r 286ef4ced216 -r fdb69dd527cd xen/drivers/passthrough/vtd/iommu.c
--- a/xen/drivers/passthrough/vtd/iommu.c Mon Nov 12 09:34:57 2012 +0100
+++ b/xen/drivers/passthrough/vtd/iommu.c Mon Nov 12 09:36:07 2012 +0100
@@ -917,7 +917,7 @@ static void __do_iommu_page_fault(struct
while (1)
{
u8 fault_reason;
- u16 source_id, cword;
+ u16 source_id;
u32 data;
u64 guest_addr;
int type;
@@ -950,14 +950,8 @@ static void __do_iommu_page_fault(struct
iommu_page_fault_do_one(iommu, type, fault_reason,
source_id, guest_addr);
- /* Tell the device to stop DMAing; we can't rely on the guest to
- * control it for us. */
- cword = pci_conf_read16(iommu->intel->drhd->segment,
- PCI_BUS(source_id), PCI_SLOT(source_id),
- PCI_FUNC(source_id), PCI_COMMAND);
- pci_conf_write16(iommu->intel->drhd->segment, PCI_BUS(source_id),
- PCI_SLOT(source_id), PCI_FUNC(source_id),
- PCI_COMMAND, cword & ~PCI_COMMAND_MASTER);
+ pci_check_disable_device(iommu->intel->drhd->segment,
+ PCI_BUS(source_id), PCI_DEVFN2(source_id));
fault_index++;
if ( fault_index > cap_num_fault_regs(iommu->cap) )
diff -r 286ef4ced216 -r fdb69dd527cd xen/include/xen/pci.h
--- a/xen/include/xen/pci.h Mon Nov 12 09:34:57 2012 +0100
+++ b/xen/include/xen/pci.h Mon Nov 12 09:36:07 2012 +0100
@@ -64,6 +64,11 @@ struct pci_dev {
const u8 devfn;
struct pci_dev_info info;
struct arch_pci_dev arch;
+ struct {
+ s_time_t time;
+ unsigned int count;
+#define PT_FAULT_THRESHOLD 10
+ } fault;
u64 vf_rlen[6];
};
@@ -107,6 +112,7 @@ int pci_hide_device(int bus, int devfn);
struct pci_dev *pci_get_pdev(int seg, int bus, int devfn);
struct pci_dev *pci_get_pdev_by_domain(
struct domain *, int seg, int bus, int devfn);
+void pci_check_disable_device(u16 seg, u8 bus, u8 devfn);
uint8_t pci_conf_read8(
unsigned int seg, unsigned int bus, unsigned int dev, unsigned int func,
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