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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-changelog] [qemu-xen stable-4.4] fix MSI injection on Xen
commit e2888602131248aae6bb49243a03ec811d6508a3
Author: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
AuthorDate: Wed Jan 13 14:59:09 2016 +0000
Commit: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
CommitDate: Mon Feb 8 15:26:16 2016 +0000
fix MSI injection on Xen
On Xen MSIs can be remapped into pirqs, which are a type of event
channels. It's mostly for the benefit of PCI passthrough devices, to
avoid the overhead of interacting with the emulated lapic.
However remapping interrupts and MSIs is also supported for emulated
devices, such as the e1000 and virtio-net.
When an interrupt or an MSI is remapped into a pirq, masking and
unmasking is done by masking and unmasking the event channel. The
masking bit on the PCI config space or MSI-X table should be ignored,
but it isn't at the moment.
As a consequence emulated devices which use MSI or MSI-X, such as
virtio-net, don't work properly (the guest doesn't receive any
notifications). The mechanism was working properly when xen_apic was
introduced, but I haven't narrowed down which commit in particular is
causing the regression.
Fix the issue by ignoring the masking bit for MSI and MSI-X which have
been remapped into pirqs.
Signed-off-by: Stefano Stabellini <stefano.stabellini@xxxxxxxxxxxxx>
Reviewed-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx>
---
hw/pci/msi.c | 9 ++++++++-
hw/pci/msix.c | 12 ++++++++++--
hw/xen/xen_pt_msi.c | 4 +---
include/hw/xen/xen.h | 1 +
xen-all.c | 9 +++++++++
xen-stub.c | 5 +++++
6 files changed, 34 insertions(+), 6 deletions(-)
diff --git a/hw/pci/msi.c b/hw/pci/msi.c
index 74fc31a..9f46e65 100644
--- a/hw/pci/msi.c
+++ b/hw/pci/msi.c
@@ -19,6 +19,7 @@
*/
#include "hw/pci/msi.h"
+#include "hw/xen/xen.h"
#include "qemu/range.h"
/* PCI_MSI_ADDRESS_LO */
@@ -253,13 +254,19 @@ void msi_reset(PCIDevice *dev)
static bool msi_is_masked(const PCIDevice *dev, unsigned int vector)
{
uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
- uint32_t mask;
+ uint32_t mask, data;
+ bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
assert(vector < PCI_MSI_VECTORS_MAX);
if (!(flags & PCI_MSI_FLAGS_MASKBIT)) {
return false;
}
+ data = pci_get_word(dev->config + msi_data_off(dev, msi64bit));
+ if (xen_is_pirq_msi(data)) {
+ return false;
+ }
+
mask = pci_get_long(dev->config +
msi_mask_off(dev, flags & PCI_MSI_FLAGS_64BIT));
return mask & (1U << vector);
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index 3430770..828509b 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -18,6 +18,7 @@
#include "hw/pci/msi.h"
#include "hw/pci/msix.h"
#include "hw/pci/pci.h"
+#include "hw/xen/xen.h"
#include "qemu/range.h"
#define MSIX_CAP_LENGTH 12
@@ -77,8 +78,15 @@ static void msix_clr_pending(PCIDevice *dev, int vector)
static bool msix_vector_masked(PCIDevice *dev, unsigned int vector, bool fmask)
{
- unsigned offset = vector * PCI_MSIX_ENTRY_SIZE +
PCI_MSIX_ENTRY_VECTOR_CTRL;
- return fmask || dev->msix_table[offset] & PCI_MSIX_ENTRY_CTRL_MASKBIT;
+ unsigned offset = vector * PCI_MSIX_ENTRY_SIZE;
+ uint32_t *data = (uint32_t *)&dev->msix_table[offset +
PCI_MSIX_ENTRY_DATA];
+ /* MSIs on Xen can be remapped into pirqs. In those cases, masking
+ * and unmasking go through the PV evtchn path. */
+ if (xen_is_pirq_msi(*data)) {
+ return false;
+ }
+ return fmask || dev->msix_table[offset + PCI_MSIX_ENTRY_VECTOR_CTRL] &
+ PCI_MSIX_ENTRY_CTRL_MASKBIT;
}
bool msix_is_masked(PCIDevice *dev, unsigned int vector)
diff --git a/hw/xen/xen_pt_msi.c b/hw/xen/xen_pt_msi.c
index 76660e5..587cfc7 100644
--- a/hw/xen/xen_pt_msi.c
+++ b/hw/xen/xen_pt_msi.c
@@ -103,9 +103,7 @@ static int msi_msix_setup(XenPCIPassthroughState *s,
assert((!is_msix && msix_entry == 0) || is_msix);
- if (gvec == 0) {
- /* if gvec is 0, the guest is asking for a particular pirq that
- * is passed as dest_id */
+ if (xen_is_pirq_msi(data)) {
*ppirq = msi_ext_dest_id(addr >> 32) | msi_dest_id(addr);
if (!*ppirq) {
/* this probably identifies an misconfiguration of the guest,
diff --git a/include/hw/xen/xen.h b/include/hw/xen/xen.h
index e1f88bf..87fe0dc 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -33,6 +33,7 @@ void xen_piix3_set_irq(void *opaque, int irq_num, int level);
void xen_piix_pci_write_config_client(uint32_t address, uint32_t val, int len);
void xen_hvm_inject_msi(uint64_t addr, uint32_t data);
void xen_cmos_set_s3_resume(void *opaque, int irq, int level);
+int xen_is_pirq_msi(uint32_t msi_data);
qemu_irq *xen_interrupt_controller_init(void);
diff --git a/xen-all.c b/xen-all.c
index 0b4d934..984c346 100644
--- a/xen-all.c
+++ b/xen-all.c
@@ -12,6 +12,7 @@
#include "hw/pci/pci.h"
#include "hw/i386/pc.h"
+#include "hw/i386/apic-msidef.h"
#include "hw/xen/xen_common.h"
#include "hw/xen/xen_backend.h"
#include "qmp-commands.h"
@@ -131,6 +132,14 @@ void xen_piix_pci_write_config_client(uint32_t address,
uint32_t val, int len)
}
}
+int xen_is_pirq_msi(uint32_t msi_data)
+{
+ /* If vector is 0, the msi is remapped into a pirq, passed as
+ * dest_id.
+ */
+ return ((msi_data & MSI_DATA_VECTOR_MASK) >> MSI_DATA_VECTOR_SHIFT) == 0;
+}
+
void xen_hvm_inject_msi(uint64_t addr, uint32_t data)
{
xen_xc_hvm_inject_msi(xen_xc, xen_domid, addr, data);
diff --git a/xen-stub.c b/xen-stub.c
index ad189a6..e78e151 100644
--- a/xen-stub.c
+++ b/xen-stub.c
@@ -38,6 +38,11 @@ void xen_cmos_set_s3_resume(void *opaque, int irq, int level)
{
}
+int xen_is_pirq_msi(uint32_t msi_data)
+{
+ return 0;
+}
+
void xen_ram_alloc(ram_addr_t ram_addr, ram_addr_t size, MemoryRegion *mr)
{
}
--
generated by git-patchbot for /home/xen/git/qemu-xen.git#stable-4.4
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