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authorWei Hu <whu@FreeBSD.org>2021-11-27 06:42:34 +0000
committerWei Hu <whu@FreeBSD.org>2021-11-30 07:43:32 +0000
commitd11e9de955ea01fe01dce58c7eb090fe0352bced (patch)
tree8e9db062bb26377261e2cde27bf41f802c2aaea5
parent5b5bbf2e7c341ec6ba569536fb14acb990d53334 (diff)
downloadsrc-d11e9de955ea01fe01dce58c7eb090fe0352bced.tar.gz
src-d11e9de955ea01fe01dce58c7eb090fe0352bced.zip
Hyper-V: vPCI: Prepopulate device bars
In recent Hyper-V releases on Windows Server 2022, vPCI code does not initialize the last 4 bit of device bar registers. This behavior change could result weird problems cuasing PCI code failure when configuring bars. Just write all 1's to those bars whose probed values are not the same as current read ones. This seems to make Hyper-V vPCI and pci_write_bar() to cooperate correctly on these releases. Reported by: khng@freebsd.org Tested by: khng@freebsd.org MFC after: 2 weeks Sponsored by: Microsoft (cherry picked from commit 75412a521f60d4b0393c730ffb284e7c6ff9d2de)
-rw-r--r--sys/dev/hyperv/pcib/vmbus_pcib.c43
1 files changed, 43 insertions, 0 deletions
diff --git a/sys/dev/hyperv/pcib/vmbus_pcib.c b/sys/dev/hyperv/pcib/vmbus_pcib.c
index 72e430c946db..c7df32044678 100644
--- a/sys/dev/hyperv/pcib/vmbus_pcib.c
+++ b/sys/dev/hyperv/pcib/vmbus_pcib.c
@@ -1356,6 +1356,47 @@ _hv_pcifront_write_config(struct hv_pci_dev *hpdev, int where, int size,
}
}
+/*
+ * The vPCI in some Hyper-V releases do not initialize the last 4
+ * bit of BAR registers. This could result weird problems causing PCI
+ * code fail to configure BAR correctly.
+ *
+ * Just write all 1's to those BARs whose probed values are not zero.
+ * This seems to make the Hyper-V vPCI and pci_write_bar() to cooperate
+ * correctly.
+ */
+
+static void
+vmbus_pcib_prepopulate_bars(struct hv_pcibus *hbus)
+{
+ struct hv_pci_dev *hpdev;
+ int i;
+
+ mtx_lock(&hbus->device_list_lock);
+ TAILQ_FOREACH(hpdev, &hbus->children, link) {
+ for (i = 0; i < 6; i++) {
+ /* Ignore empty bar */
+ if (hpdev->probed_bar[i] == 0)
+ continue;
+
+ uint32_t bar_val = 0;
+
+ _hv_pcifront_read_config(hpdev, PCIR_BAR(i),
+ 4, &bar_val);
+
+ if (hpdev->probed_bar[i] != bar_val) {
+ if (bootverbose)
+ printf("vmbus_pcib: initialize bar %d "
+ "by writing all 1s\n", i);
+
+ _hv_pcifront_write_config(hpdev, PCIR_BAR(i),
+ 4, 0xffffffff);
+ }
+ }
+ }
+ mtx_unlock(&hbus->device_list_lock);
+}
+
static void
vmbus_pcib_set_detaching(void *arg, int pending __unused)
{
@@ -1479,6 +1520,8 @@ vmbus_pcib_attach(device_t dev)
if (ret)
goto vmbus_close;
+ vmbus_pcib_prepopulate_bars(hbus);
+
hbus->pci_bus = device_add_child(dev, "pci", -1);
if (!hbus->pci_bus) {
device_printf(dev, "failed to create pci bus\n");