drm/radeon: check if device is root before getting pci speed caps

Check if the device is root rather before attempting to see what
speeds the pcie port supports.  Fixes a crash with pci passthrough
in a VM.

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=109366
Reviewed-by: Evan Quan <evan.quan@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

2 files changed, 6 insertions, 4 deletions

diff --git a/drivers/gpu/drm/radeon/ci_dpm.c b/drivers/gpu/drm/radeon/ci_dpm.c
index d587779a80b4..a97294ac96d5 100644
--- a/drivers/gpu/drm/radeon/ci_dpm.c
+++ b/drivers/gpu/drm/radeon/ci_dpm.c
@@ -5676,7 +5676,7 @@ int ci_dpm_init(struct radeon_device *rdev)
         u16 data_offset, size;
         u8 frev, crev;
         struct ci_power_info *pi;
-        enum pci_bus_speed speed_cap;
+        enum pci_bus_speed speed_cap = PCI_SPEED_UNKNOWN;
         struct pci_dev *root = rdev->pdev->bus->self;
         int ret;
 
@@ -5685,7 +5685,8 @@ int ci_dpm_init(struct radeon_device *rdev)
                 return -ENOMEM;
         rdev->pm.dpm.priv = pi;
 
-        speed_cap = pcie_get_speed_cap(root);
+        if (!pci_is_root_bus(rdev->pdev->bus))
+                speed_cap = pcie_get_speed_cap(root);
         if (speed_cap == PCI_SPEED_UNKNOWN) {
                 pi->sys_pcie_mask = 0;
         } else {
diff --git a/drivers/gpu/drm/radeon/si_dpm.c b/drivers/gpu/drm/radeon/si_dpm.c
index 8fb60b3af015..0a785ef0ab66 100644
--- a/drivers/gpu/drm/radeon/si_dpm.c
+++ b/drivers/gpu/drm/radeon/si_dpm.c
@@ -6899,7 +6899,7 @@ int si_dpm_init(struct radeon_device *rdev)
         struct ni_power_info *ni_pi;
         struct si_power_info *si_pi;
         struct atom_clock_dividers dividers;
-        enum pci_bus_speed speed_cap;
+        enum pci_bus_speed speed_cap = PCI_SPEED_UNKNOWN;
         struct pci_dev *root = rdev->pdev->bus->self;
         int ret;
 
@@ -6911,7 +6911,8 @@ int si_dpm_init(struct radeon_device *rdev)
         eg_pi = &ni_pi->eg;
         pi = &eg_pi->rv7xx;
 
-        speed_cap = pcie_get_speed_cap(root);
+        if (!pci_is_root_bus(rdev->pdev->bus))
+                speed_cap = pcie_get_speed_cap(root);
         if (speed_cap == PCI_SPEED_UNKNOWN) {
                 si_pi->sys_pcie_mask = 0;
         } else {