9 a.m.
On 5/12/24 21:45, Andrew Melnychenko wrote:
Added new capability ebpf_rss_fds for QEMU.
Added logic for loading the "RSS" eBPF program.
eBPF file descriptors passed to the QEMU.
Signed-off-by: Andrew Melnychenko <andrew(a)daynix.com>
---
src/qemu/qemu_capabilities.c | 4 +++
src/qemu/qemu_capabilities.h | 3 ++
src/qemu/qemu_command.c | 61 ++++++++++++++++++++++++++++++++++++
src/qemu/qemu_domain.c | 4 +++
src/qemu/qemu_domain.h | 3 ++
5 files changed, 75 insertions(+)
diff --git a/src/qemu/qemu_capabilities.c b/src/qemu/qemu_capabilities.c
index 09bb6ca36e..bb6a587725 100644
--- a/src/qemu/qemu_capabilities.c
+++ b/src/qemu/qemu_capabilities.c
@@ -708,6 +708,9 @@ VIR_ENUM_IMPL(virQEMUCaps,
"usb-mtp", /* QEMU_CAPS_DEVICE_USB_MTP */
"machine.virt.ras", /* QEMU_CAPS_MACHINE_VIRT_RAS */
"virtio-sound", /* QEMU_CAPS_DEVICE_VIRTIO_SOUND */
+
+ /* 460 */
+ "virtio-net.ebpf_rss_fds", /* QEMU_CAPS_VIRTIO_NET_EBPF_RSS_FDS
*/
);
@@ -1452,6 +1455,7 @@ static struct virQEMUCapsDevicePropsFlags
virQEMUCapsDevicePropsVirtioBlk[] = {
static struct virQEMUCapsDevicePropsFlags virQEMUCapsDevicePropsVirtioNet[] = {
{ "acpi-index", QEMU_CAPS_ACPI_INDEX, NULL },
{ "rss", QEMU_CAPS_VIRTIO_NET_RSS, NULL },
+ { "ebpf-rss-fds", QEMU_CAPS_VIRTIO_NET_EBPF_RSS_FDS, NULL },
};
static struct virQEMUCapsDevicePropsFlags virQEMUCapsDevicePropsPCIeRootPort[] = {
diff --git a/src/qemu/qemu_capabilities.h b/src/qemu/qemu_capabilities.h
index 371ea19bd0..e4bb137b21 100644
--- a/src/qemu/qemu_capabilities.h
+++ b/src/qemu/qemu_capabilities.h
@@ -688,6 +688,9 @@ typedef enum { /* virQEMUCapsFlags grouping marker for syntax-check
*/
QEMU_CAPS_MACHINE_VIRT_RAS, /* -machine virt,ras= */
QEMU_CAPS_DEVICE_VIRTIO_SOUND, /* -device virtio-sound-* */
+ /* 460 */
+ QEMU_CAPS_VIRTIO_NET_EBPF_RSS_FDS, /* virtio-net ebpf_rss_fds feature */
+
QEMU_CAPS_LAST /* this must always be the last item */
} virQEMUCapsFlags;
diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
index 9859ea67a4..77715cf6fe 100644
--- a/src/qemu/qemu_command.c
+++ b/src/qemu/qemu_command.c
@@ -3805,6 +3805,25 @@ qemuBuildLegacyNicStr(virDomainNetDef *net)
}
+static virJSONValue *
+qemuBuildEbpfRssArg(virDomainNetDef *net)
+{
+ qemuDomainNetworkPrivate *netpriv = QEMU_DOMAIN_NETWORK_PRIVATE(net);
+ g_autoptr(virJSONValue) props = NULL;
+
+ GSList *n;
+
+ if (netpriv->ebpfrssfds)
+ props = virJSONValueNewArray();
nitpick: A bit more convoluted than needed be.
if (!netpriv->ebpfrssfds)
return NULL;
props = virJSONValueNewArray();
+
+ for (n = netpriv->ebpfrssfds; n; n = n->next) {
+ virJSONValueArrayAppendString(props, qemuFDPassDirectGetPath(n->data));
+ }
+
+ return g_steal_pointer(&props);
+}
+
+
virJSONValue *
qemuBuildNicDevProps(virDomainDef *def,
virDomainNetDef *net,
@@ -3813,6 +3832,7 @@ qemuBuildNicDevProps(virDomainDef *def,
g_autoptr(virJSONValue) props = NULL;
char macaddr[VIR_MAC_STRING_BUFLEN];
g_autofree char *netdev = g_strdup_printf("host%s", net->info.alias);
+ g_autoptr(virJSONValue) ebpffds = NULL;
We like to declare variables in their smallest possible scope. IOW, this
should be declared ..
if (virDomainNetIsVirtioModel(net)) {
const char *tx = NULL;
.. in this block.
@@ -3863,6 +3883,8 @@ qemuBuildNicDevProps(virDomainDef *def,
if (!(props = qemuBuildVirtioDevProps(VIR_DOMAIN_DEVICE_NET, net, qemuCaps)))
return NULL;
+ ebpffds = qemuBuildEbpfRssArg(net);
+
if (virJSONValueObjectAdd(&props,
"S:tx", tx,
"T:ioeventfd",
net->driver.virtio.ioeventfd,
@@ -3887,6 +3909,7 @@ qemuBuildNicDevProps(virDomainDef *def,
"T:hash",
net->driver.virtio.rss_hash_report,
"p:host_mtu", net->mtu,
"T:failover", failover,
+ "A:ebpf-rss-fds", &ebpffds,
NULL) < 0)
return NULL;
} else {
@@ -4170,6 +4193,39 @@ qemuBuildWatchdogDevProps(const virDomainDef *def,
}
+static void
+qemuOpenEbpfRssFds(virDomainNetDef *net, virQEMUCaps *qemuCaps)
+{
+ const char *ebpfRSSObject = NULL;
+ int fds[16];
So there can be 16 FDs top? Isn't the actual value related to number of
virtio queues?
+ int nfds = 0;
+ size_t i = 0;
+ qemuDomainNetworkPrivate *netpriv = QEMU_DOMAIN_NETWORK_PRIVATE(net);
+
+ netpriv->libbpfRSSObject = NULL;
+ netpriv->ebpfrssfds = NULL;
This looks suspicious. When allocating private data, g_new0() made sure
this is zeroed out.
+
+ /* Add ebpf values */
+ if (net->driver.virtio.rss == VIR_TRISTATE_SWITCH_ON
+ && net->driver.virtio.rss_hash_report != VIR_TRISTATE_SWITCH_ON
+ && virQEMUCapsGet(qemuCaps, QEMU_CAPS_VIRTIO_NET_EBPF_RSS_FDS)) {
+ ebpfRSSObject = virQEMUCapsGetEbpf(qemuCaps, "rss");
+ nfds = qemuInterfaceLoadEbpf(ebpfRSSObject, &netpriv->libbpfRSSObject,
fds, 16);
s/G_N_ELEMENTS(fds)/16/
Also, at this point if nfds == -1 we're not sure whether we're lacking
libbpf, or libpf failed to load eBPF program. While the former should be
skipped over, the latter is a fatal error, isn't it?
+
+ if (nfds > 0) {
To increase readability of this code (by decrasing level of nesting),
I'd write this as:
if (nfds <= 0)
return;
+ for (i = 0; i < nfds; ++i) {
+ g_autofree char *name = g_strdup_printf("ebpfrssfd-%s-%zu",
net->info.alias, i);
+
+ netpriv->ebpfrssfds =
+ g_slist_prepend(netpriv->ebpfrssfds, qemuFDPassDirectNew(name,
fds + i));
+ }
+ }
+
+ netpriv->ebpfrssfds = g_slist_reverse(netpriv->ebpfrssfds);
+ }
+}
+
+
Michal