@@ -179,6 +179,9 @@ struct machdep_calls {
resource_size_t (*pcibios_default_alignment)(void);
+ /* Called when determining PCI resource alignment */
+ int (*pcibios_ignore_alignment_request)(void);
+
#ifdef CONFIG_PCI_IOV
void (*pcibios_fixup_sriov)(struct pci_dev *pdev);
resource_size_t (*pcibios_iov_resource_alignment)(struct pci_dev *, int resno);
@@ -238,6 +238,15 @@ resource_size_t pcibios_default_alignment(void)
return 0;
}
+resource_size_t pcibios_ignore_alignment_request(void)
+{
+ if (ppc_md.pcibios_ignore_alignment_request)
+ return ppc_md.pcibios_ignore_alignment_request();
+
+ /* Fall back to default method of checking PCI_PROBE_ONLY */
+ return pci_has_flag(PCI_PROBE_ONLY);
+}
+
#ifdef CONFIG_PCI_IOV
resource_size_t pcibios_iov_resource_alignment(struct pci_dev *pdev, int resno)
{
@@ -82,6 +82,8 @@ EXPORT_SYMBOL(CMO_PageSize);
int fwnmi_active; /* TRUE if an FWNMI handler is present */
+int initial_pci_init_done; /* TRUE if initial pcibios init has completed */
+
static void pSeries_show_cpuinfo(struct seq_file *m)
{
struct device_node *root;
@@ -749,6 +751,23 @@ static resource_size_t pseries_pci_iov_resource_alignment(struct pci_dev *pdev,
}
#endif
+static void pseries_after_init(void)
+{
+ initial_pci_init_done = 1;
+}
+
+static int pseries_ignore_alignment_request(void)
+{
+ if (initial_pci_init_done)
+ /*
+ * Allow custom alignments after init for things
+ * like PCI hotplugging.
+ */
+ return 0;
+
+ return pci_has_flag(PCI_PROBE_ONLY);
+}
+
static void __init pSeries_setup_arch(void)
{
set_arch_panic_timeout(10, ARCH_PANIC_TIMEOUT);
@@ -797,6 +816,9 @@ static void __init pSeries_setup_arch(void)
}
ppc_md.pcibios_root_bridge_prepare = pseries_root_bridge_prepare;
+ ppc_md.pcibios_after_init = pseries_after_init;
+ ppc_md.pcibios_ignore_alignment_request =
+ pseries_ignore_alignment_request;
}
static void pseries_panic(char *str)
On pseries, custom PCI resource alignment specified with the commandline argument pci=resource_alignment is disabled due to PCI resources being managed by the firmware. However, in the case of PCI hotplug the resources are managed by the kernel, so custom alignments should be honored in these cases. This is done by only honoring custom alignments after initial PCI initialization is done, to ensure that all devices managed by the firmware are excluded. Without this ability, sub-page BARs sometimes get mapped in between page boundaries for hotplugged devices and are therefore unusable with the VFIO framework. This change allows users to request page alignment for devices they wish to access via VFIO using the pci=resource_alignment commandline argument. In the future, this could be extended to provide page-aligned resources by default for hotplugged devices, similar to what is done on powernv by commit 382746376993 ("powerpc/powernv: Override pcibios_default_alignment() to force PCI devices to be page aligned") Signed-off-by: Shawn Anastasio <shawn@anastas.io> --- arch/powerpc/include/asm/machdep.h | 3 +++ arch/powerpc/kernel/pci-common.c | 9 +++++++++ arch/powerpc/platforms/pseries/setup.c | 22 ++++++++++++++++++++++ 3 files changed, 34 insertions(+)