[Qemu-devel] [PATCH 1/3] msi/msix: added functions to API to set up message address and data

[Alexey Kardashevskiy <aik@ozlabs.ru>]

Normally QEMU expects the guest to initialize MSI/MSIX vectors.
However on POWER the guest uses RTAS subsystem to configure MSI/MSIX and
does not write these vectors to device's config space or MSIX BAR.

On the other hand, msi_notify()/msix_notify() write to these vectors to
signal the guest about an interrupt so we have to write correct vectors
to the devices in order not to change every user of MSI/MSIX.

The first aim is to support MSIX for virtio-pci on POWER. There is
another patch for POWER coming which introduces a special memory region
where MSI/MSIX vectors point to.

Signed-off-by: Alexey Kardashevskiy <aik@ozlabs.ru>
---
 hw/msi.c  |   14 ++++++++++++++
 hw/msi.h  |    1 +
 hw/msix.c |   10 ++++++++++
 hw/msix.h |    3 +++
 4 files changed, 28 insertions(+), 0 deletions(-)

diff --git a/hw/msi.c b/hw/msi.c
index 5d6ceb6..124878a 100644
--- a/hw/msi.c
+++ b/hw/msi.c
@@ -358,3 +358,17 @@ unsigned int msi_nr_vectors_allocated(const PCIDevice *dev)
     uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
     return msi_nr_vectors(flags);
 }
+
+void msi_set_address_data(PCIDevice *dev, uint64_t address, uint16_t data)
+{
+    uint16_t flags = pci_get_word(dev->config + msi_flags_off(dev));
+    bool msi64bit = flags & PCI_MSI_FLAGS_64BIT;
+
+    if (msi64bit) {
+        pci_set_quad(dev->config + msi_address_lo_off(dev), address);
+    } else {
+        pci_set_long(dev->config + msi_address_lo_off(dev), address);
+    }
+    pci_set_word(dev->config + msi_data_off(dev, msi64bit), data);
+}
+
diff --git a/hw/msi.h b/hw/msi.h
index 3040bb0..0acf434 100644
--- a/hw/msi.h
+++ b/hw/msi.h
@@ -34,6 +34,7 @@ void msi_reset(PCIDevice *dev);
 void msi_notify(PCIDevice *dev, unsigned int vector);
 void msi_write_config(PCIDevice *dev, uint32_t addr, uint32_t val, int len);
 unsigned int msi_nr_vectors_allocated(const PCIDevice *dev);
+void msi_set_address_data(PCIDevice *dev, uint64_t address, uint16_t data);

 static inline bool msi_present(const PCIDevice *dev)
 {
diff --git a/hw/msix.c b/hw/msix.c
index 3835eaa..c57c299 100644
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -414,3 +414,13 @@ void msix_unuse_all_vectors(PCIDevice *dev)
         return;
     msix_free_irq_entries(dev);
 }
+
+void msix_set_address_data(PCIDevice *dev, int vector,
+                           uint64_t address, uint32_t data)
+{
+    uint8_t *table_entry = dev->msix_table_page + vector * PCI_MSIX_ENTRY_SIZE;
+    pci_set_quad(table_entry + PCI_MSIX_ENTRY_LOWER_ADDR, address);
+    pci_set_long(table_entry + PCI_MSIX_ENTRY_DATA, data);
+    table_entry[PCI_MSIX_ENTRY_VECTOR_CTRL] &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
+}
+
diff --git a/hw/msix.h b/hw/msix.h
index 5aba22b..e6bb696 100644
--- a/hw/msix.h
+++ b/hw/msix.h
@@ -29,4 +29,7 @@ void msix_notify(PCIDevice *dev, unsigned vector);

 void msix_reset(PCIDevice *dev);

+void msix_set_address_data(PCIDevice *dev, int vector,
+                           uint64_t address, uint32_t data);
+
 #endif
-- 
1.7.7.3