[PATCH] msi/msix: added API to set MSI message address and data

[Alexey Kardashevskiy <aik@xxxxxxxxx>]

Added (msi|msix)_set_message() function for whoever might
want to use them.

Currently msi_notify()/msix_notify() write to these vectors to
signal the guest about an interrupt so the correct values have to
written there by the guest or QEMU.

For example, POWER guest never initializes MSI/MSIX vectors, instead
it uses RTAS hypercalls. So in order to support MSIX for virtio-pci on
POWER we have to initialize MSI/MSIX message from QEMU.

Signed-off-by: Alexey Kardashevskiy <aik@xxxxxxxxx>
---
 hw/msi.c  |   13 +++++++++++++
 hw/msi.h  |    1 +
 hw/msix.c |    9 +++++++++
 hw/msix.h |    2 ++
 4 files changed, 25 insertions(+)

diff --git a/hw/msi.c b/hw/msi.c
index 5233204..cc6102f 100644
--- a/hw/msi.c
+++ b/hw/msi.c
@@ -105,6 +105,19 @@ static inline uint8_t msi_pending_off(const PCIDevice* dev, bool msi64bit)
     return dev->msi_cap + (msi64bit ? PCI_MSI_PENDING_64 : PCI_MSI_PENDING_32);
 }
 
+void msi_set_message(PCIDevice *dev, MSIMessage msg)
+{
+    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), msg.address);
+    } else {
+        pci_set_long(dev->config + msi_address_lo_off(dev), msg.address);
+    }
+    pci_set_word(dev->config + msi_data_off(dev, msi64bit), msg.data);
+}
+
 bool msi_enabled(const PCIDevice *dev)
 {
     return msi_present(dev) &&
diff --git a/hw/msi.h b/hw/msi.h
index 75747ab..6ec1f99 100644
--- a/hw/msi.h
+++ b/hw/msi.h
@@ -31,6 +31,7 @@ struct MSIMessage {
 
 extern bool msi_supported;
 
+void msi_set_message(PCIDevice *dev, MSIMessage msg);
 bool msi_enabled(const PCIDevice *dev);
 int msi_init(struct PCIDevice *dev, uint8_t offset,
              unsigned int nr_vectors, bool msi64bit, bool msi_per_vector_mask);
diff --git a/hw/msix.c b/hw/msix.c
index ded3c55..5f7d6d3 100644
--- a/hw/msix.c
+++ b/hw/msix.c
@@ -45,6 +45,15 @@ static MSIMessage msix_get_message(PCIDevice *dev, unsigned vector)
     return msg;
 }
 
+void msix_set_message(PCIDevice *dev, int vector, struct MSIMessage msg)
+{
+    uint8_t *table_entry = dev->msix_table_page + vector * PCI_MSIX_ENTRY_SIZE;
+
+    pci_set_quad(table_entry + PCI_MSIX_ENTRY_LOWER_ADDR, msg.address);
+    pci_set_long(table_entry + PCI_MSIX_ENTRY_DATA, msg.data);
+    table_entry[PCI_MSIX_ENTRY_VECTOR_CTRL] &= ~PCI_MSIX_ENTRY_CTRL_MASKBIT;
+}
+
 /* Add MSI-X capability to the config space for the device. */
 /* Given a bar and its size, add MSI-X table on top of it
  * and fill MSI-X capability in the config space.
diff --git a/hw/msix.h b/hw/msix.h
index 50aee82..26a437e 100644
--- a/hw/msix.h
+++ b/hw/msix.h
@@ -4,6 +4,8 @@
 #include "qemu-common.h"
 #include "pci.h"
 
+void msix_set_message(PCIDevice *dev, int vector, MSIMessage msg);
+
 int msix_init(PCIDevice *pdev, unsigned short nentries,
               MemoryRegion *bar,
               unsigned bar_nr, unsigned bar_size);
-- 
1.7.10
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