These rules will make it possible for libvirt to
automatically assign PCI addresses in a way that
respects any isolation constraints devices might
have.
Signed-off-by: Andrea Bolognani <abologna@xxxxxxxxxx>
Reviewed-by: Laine Stump <laine@xxxxxxxxx>
---
src/conf/domain_addr.c | 73 +++++++++++++++++++++++++++++++++++++++++++++++---
src/conf/domain_addr.h | 3 +++
2 files changed, 72 insertions(+), 4 deletions(-)
diff --git a/src/conf/domain_addr.c b/src/conf/domain_addr.c
index bb095a3..531fc68 100644
--- a/src/conf/domain_addr.c
+++ b/src/conf/domain_addr.c
@@ -369,6 +369,20 @@ virDomainPCIAddressBusIsFullyReserved(virDomainPCIAddressBusPtr bus)
}
+bool
+virDomainPCIAddressBusIsEmpty(virDomainPCIAddressBusPtr bus)
+{
+ size_t i;
+
+ for (i = bus->minSlot; i <= bus->maxSlot; i++) {
+ if (bus->slot[i].functions)
+ return false;
+ }
+
+ return true;
+}
+
+
/* Ensure addr fits in the address set, by expanding it if needed
*
* Return value:
@@ -548,7 +562,7 @@ static int ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2)
virDomainPCIAddressReserveAddrInternal(virDomainPCIAddressSetPtr addrs,
virPCIDeviceAddressPtr addr,
virDomainPCIConnectFlags flags,
- unsigned int isolationGroup ATTRIBUTE_UNUSED,
+ unsigned int isolationGroup,
bool fromConfig)
{
int ret = -1;
@@ -586,6 +600,26 @@ virDomainPCIAddressReserveAddrInternal(virDomainPCIAddressSetPtr addrs,
bus->slot[addr->slot].aggregate = true;
}
+ if (virDomainPCIAddressBusIsEmpty(bus) && !bus->isolationGroupLocked) {
+ /* The first device decides the isolation group for the
+ * entire bus */
+ bus->isolationGroup = isolationGroup;
+ VIR_DEBUG("PCI bus %.4x:%.2x assigned isolation group %u because of "
+ "first device %s",
+ addr->domain, addr->bus, isolationGroup, addrStr);
+ } else if (bus->isolationGroup != isolationGroup && fromConfig) {
+ /* If this is not the first function and its isolation group
+ * doesn't match the bus', then it should not be using this
+ * address. However, if the address comes from the user then
+ * we comply with the request and change the isolation group
+ * back to the default (because at that point isolation can't
+ * be guaranteed anymore) */
+ bus->isolationGroup = 0;
+ VIR_DEBUG("PCI bus %.4x:%.2x assigned isolation group %u because of "
+ "user assigned address %s",
+ addr->domain, addr->bus, isolationGroup, addrStr);
+ }
+
/* mark the requested function as reserved */
bus->slot[addr->slot].functions |= (1 << addr->function);
VIR_DEBUG("Reserving PCI address %s (aggregate='%s')", addrStr,
@@ -763,7 +797,7 @@ static int ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2)
virDomainPCIAddressGetNextAddr(virDomainPCIAddressSetPtr addrs,
virPCIDeviceAddressPtr next_addr,
virDomainPCIConnectFlags flags,
- unsigned int isolationGroup ATTRIBUTE_UNUSED,
+ unsigned int isolationGroup,
int function)
{
virPCIDeviceAddress a = { 0 };
@@ -779,12 +813,41 @@ virDomainPCIAddressGetNextAddr(virDomainPCIAddressSetPtr addrs,
else
a.function = function;
- /* "Begin at the beginning," the King said, very gravely, "and go on
- * till you come to the end: then stop." */
+ /* When looking for a suitable bus for the device, start by being
+ * very strict and ignoring all those where the isolation groups
+ * don't match. This ensures all devices sharing the same isolation
+ * group will end up on the same bus */
for (a.bus = 0; a.bus < addrs->nbuses; a.bus++) {
virDomainPCIAddressBusPtr bus = &addrs->buses[a.bus];
bool found = false;
+ if (bus->isolationGroup != isolationGroup)
+ continue;
+
+ a.slot = bus->minSlot;
+
+ if (virDomainPCIAddressFindUnusedFunctionOnBus(bus, &a, function,
+ flags, &found) < 0) {
+ goto error;
+ }
+
+ if (found)
+ goto success;
+ }
+
+ /* We haven't been able to find a perfectly matching bus, but we
+ * might still be able to make this work by altering the isolation
+ * group for a bus that's currently empty. So let's try that */
+ for (a.bus = 0; a.bus < addrs->nbuses; a.bus++) {
+ virDomainPCIAddressBusPtr bus = &addrs->buses[a.bus];
+ bool found = false;
+
+ /* We can only change the isolation group for a bus when
+ * plugging in the first device; moreover, some buses are
+ * prevented from ever changing it */
+ if (!virDomainPCIAddressBusIsEmpty(bus) || bus->isolationGroupLocked)
+ continue;
+
a.slot = bus->minSlot;
if (virDomainPCIAddressFindUnusedFunctionOnBus(bus, &a, function,
@@ -792,6 +855,8 @@ virDomainPCIAddressGetNextAddr(virDomainPCIAddressSetPtr addrs,
goto error;
}
+ /* The isolation group for the bus will actually be changed
+ * later, in virDomainPCIAddressReserveAddrInternal() */
if (found)
goto success;
}
diff --git a/src/conf/domain_addr.h b/src/conf/domain_addr.h
index ac6d64f..205e7cf 100644
--- a/src/conf/domain_addr.h
+++ b/src/conf/domain_addr.h
@@ -142,6 +142,9 @@ int virDomainPCIAddressBusSetModel(virDomainPCIAddressBusPtr bus,
bool virDomainPCIAddressBusIsFullyReserved(virDomainPCIAddressBusPtr bus)
ATTRIBUTE_NONNULL(1);
+bool virDomainPCIAddressBusIsEmpty(virDomainPCIAddressBusPtr bus)
+ ATTRIBUTE_NONNULL(1);
+
bool virDomainPCIAddressSlotInUse(virDomainPCIAddressSetPtr addrs,
virPCIDeviceAddressPtr addr)
ATTRIBUTE_NONNULL(1) ATTRIBUTE_NONNULL(2);
--
2.7.5
--
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