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authorJan Kiszka <jan.kiszka@siemens.com>2018-03-07 08:39:13 +0100
committerThomas Gleixner <tglx@linutronix.de>2018-03-08 12:30:37 +0100
commit690f4304104f37e473bd5e43fc5247f5cd35b225 (patch)
tree0df929dd720cb38ad5f35ea94ab850dd7a06553c /arch/x86/pci
parent63338a38db955cb4e0352c11b78732157c78d30b (diff)
PCI: Scan all functions when running over Jailhouse
Per PCIe r4.0, sec 7.5.1.1.9, multi-function devices are required to have a function 0. Therefore, Linux scans for devices at function 0 (devfn 0/8/16/...) and only scans for other functions if function 0 has its Multi-Function Device bit set or ARI or SR-IOV indicate there are more functions. The Jailhouse hypervisor may pass individual functions of a multi-function device to a guest without passing function 0, which means a Linux guest won't find them. Change Linux PCI probing so it scans all function numbers when running as a guest over Jailhouse. This is technically prohibited by the spec, so it is possible that PCI devices without the Multi-Function Device bit set may have unexpected behavior in response to this probe. Originally-by: Benedikt Spranger <b.spranger@linutronix.de> Signed-off-by: Jan Kiszka <jan.kiszka@siemens.com> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com> Acked-by: Bjorn Helgaas <bhelgaas@google.com> Cc: jailhouse-dev@googlegroups.com Cc: Benedikt Spranger <b.spranger@linutronix.de> Cc: linux-pci@vger.kernel.org Cc: virtualization@lists.linux-foundation.org Link: https://lkml.kernel.org/r/06e279b2a3e06cf6689ab3975f8ab592bba02362.1520408357.git.jan.kiszka@siemens.com
Diffstat (limited to 'arch/x86/pci')
-rw-r--r--arch/x86/pci/legacy.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/arch/x86/pci/legacy.c b/arch/x86/pci/legacy.c
index 1cb01abcb1be..dfbe6ac38830 100644
--- a/arch/x86/pci/legacy.c
+++ b/arch/x86/pci/legacy.c
@@ -4,6 +4,7 @@
#include <linux/init.h>
#include <linux/export.h>
#include <linux/pci.h>
+#include <asm/jailhouse_para.h>
#include <asm/pci_x86.h>
/*
@@ -34,13 +35,14 @@ int __init pci_legacy_init(void)
void pcibios_scan_specific_bus(int busn)
{
+ int stride = jailhouse_paravirt() ? 1 : 8;
int devfn;
u32 l;
if (pci_find_bus(0, busn))
return;
- for (devfn = 0; devfn < 256; devfn += 8) {
+ for (devfn = 0; devfn < 256; devfn += stride) {
if (!raw_pci_read(0, busn, devfn, PCI_VENDOR_ID, 2, &l) &&
l != 0x0000 && l != 0xffff) {
DBG("Found device at %02x:%02x [%04x]\n", busn, devfn, l);