From: Stewart Hildebrand <stewart.hildebr...@amd.com>
Enable the use of IOMMU + PCI in dom0 without having to specify
"pci-passthrough=yes". Due to possible platform specific dependencies
of the PCI host, we rely on dom0 to initialize it and perform
a PHYSDEVOP_pci_device_add/remove call to add each device to SMMU.
PHYSDEVOP_pci_device_reset is left untouched as it does not have the
pci_passthrough_enabled check.
Because pci_passthrough is not always enabled on all architectures, add
a new function arch_pci_device_physdevop that checks if we need to enable
a subset of the PCI subsystem related to managing IOMMU configuration
for PCI devices.
Enable pci_init() for initializing Xen's internal PCI subsystem, and
allow PHYSDEVOP_pci_device_add when pci-passthrough is disabled.
Signed-off-by: Stewart Hildebrand <stewart.hildebr...@amd.com>
Signed-off-by: Mykyta Poturai <mykyta_potu...@epam.com>
Reviewed-by: Stefano Stabellini <sstabell...@kernel.org>
---
hmm. Since
dec9e02f3190 ("xen: avoid generation of stub <asm/pci.h> header")
Should we also move is_pci_passthrough_enabled() back to
xen/arch/arm/include/asm/pci.h ?
Not sure if PPC/RISC-V will plan on using this check.
v10->v11:
* always_inline -> inline
* add comments
* clarify reset sub-op handling in the commit message
v9->v10:
* move iommu_enabled check in a separate arch function
* add Stefano's RB
v8->v9:
* move iommu_enabled check inside is_pci_passthrough_enabled()
v7->v8:
* bring back x86 definition of is_pci_passthrough_enabled()
v6->v7:
* remove x86 definition of is_pci_passthrough_enabled()
* update comments
* make pci_physdev_op checks stricter
v5->v6:
* new patch - this effectively replaces
("Revert "xen/arm: Add cmdline boot option "pci-passthrough = <boolean>""")
---
xen/arch/arm/include/asm/pci.h | 2 ++
xen/arch/arm/pci/pci.c | 14 +++++++++++++-
xen/arch/x86/include/asm/pci.h | 6 ++++++
xen/drivers/pci/physdev.c | 4 ++--
xen/include/xen/pci.h | 5 +++++
5 files changed, 28 insertions(+), 3 deletions(-)
diff --git a/xen/arch/arm/include/asm/pci.h b/xen/arch/arm/include/asm/pci.h
index 7f77226c9b..d6e05f16b0 100644
--- a/xen/arch/arm/include/asm/pci.h
+++ b/xen/arch/arm/include/asm/pci.h
@@ -128,6 +128,8 @@ int pci_host_bridge_mappings(struct domain *d);
bool pci_check_bar(const struct pci_dev *pdev, mfn_t start, mfn_t end);
+bool arch_pci_device_physdevop(void);
+
#else /*!CONFIG_HAS_PCI*/
struct pci_dev;
diff --git a/xen/arch/arm/pci/pci.c b/xen/arch/arm/pci/pci.c
index 8d9692c92e..ca825ee3a6 100644
--- a/xen/arch/arm/pci/pci.c
+++ b/xen/arch/arm/pci/pci.c
@@ -16,6 +16,7 @@
#include <xen/device_tree.h>
#include <xen/errno.h>
#include <xen/init.h>
+#include <xen/iommu.h>
#include <xen/param.h>
#include <xen/pci.h>
@@ -75,6 +76,17 @@ static int __init acpi_pci_init(void)
}
#endif
+/*
+ * Platform-specific PCI host dependencies require dom0 to handle
+ * initialization and issue PHYSDEVOP_pci_device_add/remove calls for SMMU
+ * device registration. This check is used to enable the minimal PCI
+ * subsystem required for dom0 operation when PCI passthrough is disabled.
+ */
+bool arch_pci_device_physdevop(void)
+{
+ return iommu_enabled;
+}
+
/* By default pci passthrough is disabled. */
bool __read_mostly pci_passthrough_enabled;
boolean_param("pci-passthrough", pci_passthrough_enabled);
@@ -85,7 +97,7 @@ static int __init pci_init(void)
* Enable PCI passthrough when has been enabled explicitly
* (pci-passthrough=on).
*/
- if ( !pci_passthrough_enabled )
+ if ( !is_pci_passthrough_enabled() && !arch_pci_device_physdevop() )
return 0;
if ( pci_add_segment(0) )
diff --git a/xen/arch/x86/include/asm/pci.h b/xen/arch/x86/include/asm/pci.h
index fd5480d67d..61d8043fa3 100644
--- a/xen/arch/x86/include/asm/pci.h
+++ b/xen/arch/x86/include/asm/pci.h
@@ -67,4 +67,10 @@ static inline bool pci_check_bar(const struct pci_dev *pdev,
return is_memory_hole(start, end);
}
+/* PCI passthrough is always enabled on x86 so no special handling is needed */
+static inline bool arch_pci_device_physdevop(void)
+{
+ return false;
+}
+
#endif /* __X86_PCI_H__ */
diff --git a/xen/drivers/pci/physdev.c b/xen/drivers/pci/physdev.c
index 0161a85e1e..21c8a3a90e 100644
--- a/xen/drivers/pci/physdev.c
+++ b/xen/drivers/pci/physdev.c
@@ -19,7 +19,7 @@ ret_t pci_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void)
arg)
struct pci_dev_info pdev_info;
nodeid_t node = NUMA_NO_NODE;
- if ( !is_pci_passthrough_enabled() )
+ if ( !is_pci_passthrough_enabled() && !arch_pci_device_physdevop())
return -EOPNOTSUPP;
ret = -EFAULT;
@@ -57,7 +57,7 @@ ret_t pci_physdev_op(int cmd, XEN_GUEST_HANDLE_PARAM(void)
arg)
case PHYSDEVOP_pci_device_remove: {
struct physdev_pci_device dev;
- if ( !is_pci_passthrough_enabled() )
+ if ( !is_pci_passthrough_enabled() && !arch_pci_device_physdevop())
return -EOPNOTSUPP;
ret = -EFAULT;
diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
index ef60196653..130c2a8c1a 100644
--- a/xen/include/xen/pci.h
+++ b/xen/include/xen/pci.h
@@ -79,6 +79,11 @@ static inline bool is_pci_passthrough_enabled(void)
return false;
}
+static inline bool arch_pci_device_physdevop(void)
+{
+ return false;
+}
+
#endif
struct pci_dev_info {
--
2.34.1
