[Xen-devel] [PATCH 3/3] msi: Handle remappable format interrupt request

[Lan Tianyu <tianyu.lan@xxxxxxxxx>]

From: Chao Gao <chao.gao@xxxxxxxxx>

According to VT-d spec Interrupt Remapping and Interrupt Posting ->
Interrupt Remapping -> Interrupt Request Formats On Intel 64
Platforms, fields of MSI data register have changed. This patch
avoids wrongly regarding a remappable format interrupt request as
an interrupt binded with an event channel.

Signed-off-by: Chao Gao <chao.gao@xxxxxxxxx>
Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
---
 hw/pci/msi.c         | 5 +++--
 hw/pci/msix.c        | 4 +++-
 hw/xen/xen_pt_msi.c  | 2 +-
 include/hw/xen/xen.h | 2 +-
 xen-hvm-stub.c       | 2 +-
 xen-hvm.c            | 8 +++++++-
 6 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/hw/pci/msi.c b/hw/pci/msi.c
index a87b227..3713ea6 100644
--- a/hw/pci/msi.c
+++ b/hw/pci/msi.c
@@ -289,7 +289,7 @@ 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, data;
+    uint32_t mask, data, addr_lo;
     bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
     assert(vector < PCI_MSI_VECTORS_MAX);
 
@@ -298,7 +298,8 @@ static bool msi_is_masked(const PCIDevice *dev, unsigned 
int vector)
     }
 
     data = pci_get_word(dev->config + msi_data_off(dev, msi64bit));
-    if (xen_is_pirq_msi(data)) {
+    addr_lo = pci_get_long(dev->config + msi_address_lo_off(dev));
+    if (xen_is_pirq_msi(addr_lo, data)) {
         return false;
     }
 
diff --git a/hw/pci/msix.c b/hw/pci/msix.c
index 0ec1cb1..6dda83c 100644
--- a/hw/pci/msix.c
+++ b/hw/pci/msix.c
@@ -81,9 +81,11 @@ static bool msix_vector_masked(PCIDevice *dev, unsigned int 
vector, bool fmask)
 {
     unsigned offset = vector * PCI_MSIX_ENTRY_SIZE;
     uint8_t *data = &dev->msix_table[offset + PCI_MSIX_ENTRY_DATA];
+    uint8_t *addr_lo = &dev->msix_table[offset + PCI_MSIX_ENTRY_LOWER_ADDR];
     /* MSIs on Xen can be remapped into pirqs. In those cases, masking
      * and unmasking go through the PV evtchn path. */
-    if (xen_enabled() && xen_is_pirq_msi(pci_get_long(data))) {
+    if (xen_enabled() && xen_is_pirq_msi(pci_get_long(addr_lo),
+                                         pci_get_long(data))) {
         return false;
     }
     return fmask || dev->msix_table[offset + PCI_MSIX_ENTRY_VECTOR_CTRL] &
diff --git a/hw/xen/xen_pt_msi.c b/hw/xen/xen_pt_msi.c
index 26a69d9..68da0e4 100644
--- a/hw/xen/xen_pt_msi.c
+++ b/hw/xen/xen_pt_msi.c
@@ -114,7 +114,7 @@ static int msi_msix_setup(XenPCIPassthroughState *s,
 
     assert((!is_msix && msix_entry == 0) || is_msix);
 
-    if (xen_is_pirq_msi(data)) {
+    if (xen_is_pirq_msi(addr, 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 a8f3afb..b1ef41e 100644
--- a/include/hw/xen/xen.h
+++ b/include/hw/xen/xen.h
@@ -33,7 +33,7 @@ int xen_pci_slot_get_pirq(PCIDevice *pci_dev, int irq_num);
 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);
-int xen_is_pirq_msi(uint32_t msi_data);
+int xen_is_pirq_msi(uint32_t msi_addr_lo, uint32_t msi_data);
 
 qemu_irq *xen_interrupt_controller_init(void);
 
diff --git a/xen-hvm-stub.c b/xen-hvm-stub.c
index c500325..a3a3bb3 100644
--- a/xen-hvm-stub.c
+++ b/xen-hvm-stub.c
@@ -31,7 +31,7 @@ void xen_hvm_inject_msi(uint64_t addr, uint32_t data)
 {
 }
 
-int xen_is_pirq_msi(uint32_t msi_data)
+int xen_is_pirq_msi(uint32_t msi_addr_lo, uint32_t msi_data)
 {
     return 0;
 }
diff --git a/xen-hvm.c b/xen-hvm.c
index 0892361..9f1a7bd 100644
--- a/xen-hvm.c
+++ b/xen-hvm.c
@@ -146,8 +146,14 @@ void xen_piix_pci_write_config_client(uint32_t address, 
uint32_t val, int len)
     }
 }
 
-int xen_is_pirq_msi(uint32_t msi_data)
+int xen_is_pirq_msi(uint32_t msi_addr_lo, uint32_t msi_data)
 {
+    /* If the MSI address is configured in remapping format, the MSI will not
+     * be remapped into a pirq.
+     */
+    if (msi_addr_lo & MSI_ADDR_IF_MASK) {
+        return 0;
+    }
     /* If vector is 0, the msi is remapped into a pirq, passed as
      * dest_id.
      */
-- 
1.8.3.1


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