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authorYijing Wang <wangyijing@huawei.com>2014-10-27 10:44:36 +0800
committerBjorn Helgaas <bhelgaas@google.com>2014-11-06 16:34:39 -0700
commit38737d82f9f0168955f9944c3f8bd3bb262c7e88 (patch)
treed43a3bc4a84dad0e3a178f74478ea6996c0773c8
parentf114040e3ea6e07372334ade75d1ee0775c355e1 (diff)
PCI/MSI: Add pci_msi_ignore_mask to prevent writes to MSI/MSI-X Mask Bits
MSI-X vector Mask Bits are in MSI-X Tables in PCI memory space. Xen PV guests can't write to those tables. MSI vector Mask Bits are in PCI configuration space. Xen PV guests can write to config space, but those writes are ignored. Commit 0e4ccb1505a9 ("PCI: Add x86_msi.msi_mask_irq() and msix_mask_irq()") added a way to override default_mask_msi_irqs() and default_mask_msix_irqs() so they can be no-ops in Xen guests, but this is more complicated than necessary. Add "pci_msi_ignore_mask" in the core PCI MSI code. If set, default_mask_msi_irqs() and default_mask_msix_irqs() return without doing anything. This is less flexible, but much simpler. [bhelgaas: changelog] Signed-off-by: Yijing Wang <wangyijing@huawei.com> Signed-off-by: Bjorn Helgaas <bhelgaas@google.com> Reviewed-by: David Vrabel <david.vrabel@citrix.com> CC: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> CC: xen-devel@lists.xenproject.org
-rw-r--r--arch/x86/pci/xen.c2
-rw-r--r--drivers/pci/msi.c7
-rw-r--r--include/linux/msi.h1
3 files changed, 9 insertions, 1 deletions
diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 093f5f4272d3..5ef62ed20ba4 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -427,6 +427,7 @@ int __init pci_xen_init(void)
x86_msi.teardown_msi_irqs = xen_teardown_msi_irqs;
x86_msi.msi_mask_irq = xen_nop_msi_mask_irq;
x86_msi.msix_mask_irq = xen_nop_msix_mask_irq;
+ pci_msi_ignore_mask = 1;
#endif
return 0;
}
@@ -508,6 +509,7 @@ int __init pci_xen_initial_domain(void)
x86_msi.restore_msi_irqs = xen_initdom_restore_msi_irqs;
x86_msi.msi_mask_irq = xen_nop_msi_mask_irq;
x86_msi.msix_mask_irq = xen_nop_msix_mask_irq;
+ pci_msi_ignore_mask = 1;
#endif
xen_setup_acpi_sci();
__acpi_register_gsi = acpi_register_gsi_xen;
diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c
index 9fab30af0e75..066c2fb9763a 100644
--- a/drivers/pci/msi.c
+++ b/drivers/pci/msi.c
@@ -23,6 +23,7 @@
#include "pci.h"
static int pci_msi_enable = 1;
+int pci_msi_ignore_mask;
#define msix_table_size(flags) ((flags & PCI_MSIX_FLAGS_QSIZE) + 1)
@@ -167,7 +168,7 @@ u32 default_msi_mask_irq(struct msi_desc *desc, u32 mask, u32 flag)
{
u32 mask_bits = desc->masked;
- if (!desc->msi_attrib.maskbit)
+ if (pci_msi_ignore_mask || !desc->msi_attrib.maskbit)
return 0;
mask_bits &= ~mask;
@@ -199,6 +200,10 @@ u32 default_msix_mask_irq(struct msi_desc *desc, u32 flag)
u32 mask_bits = desc->masked;
unsigned offset = desc->msi_attrib.entry_nr * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_VECTOR_CTRL;
+
+ if (pci_msi_ignore_mask)
+ return 0;
+
mask_bits &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
if (flag)
mask_bits |= PCI_MSIX_ENTRY_CTRL_MASKBIT;
diff --git a/include/linux/msi.h b/include/linux/msi.h
index 44f4746d033b..86dc501a1534 100644
--- a/include/linux/msi.h
+++ b/include/linux/msi.h
@@ -10,6 +10,7 @@ struct msi_msg {
u32 data; /* 16 bits of msi message data */
};
+extern int pci_msi_ignore_mask;
/* Helper functions */
struct irq_data;
struct msi_desc;