diff mbox series

[RFC,XEN,v15,3/4] tools: Add new function to get gsi from dev

Message ID 20240911065832.1591273-4-Jiqian.Chen@amd.com (mailing list archive)
State Superseded
Headers show
Series Support device passthrough when dom0 is PVH on Xen | expand

Commit Message

Chen, Jiqian Sept. 11, 2024, 6:58 a.m. UTC
On PVH dom0, when passthrough a device to domU, QEMU and xl tools
want to use gsi number to do pirq mapping, see QEMU code
xen_pt_realize->xc_physdev_map_pirq, and xl code
pci_add_dm_done->xc_physdev_map_pirq, but in current codes, the gsi
number is got from file /sys/bus/pci/devices/<sbdf>/irq, that is
wrong, because irq is not equal with gsi, they are in different
spaces, so pirq mapping fails.

And in current codes, there is no method to get gsi for userspace.
For above purpose, add new function to get gsi, and the
corresponding ioctl is implemented on linux kernel side.

Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
Signed-off-by: Huang Rui <ray.huang@amd.com>
Signed-off-by: Chen Jiqian <Jiqian.Chen@amd.com>
Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
---
RFC: it needs to wait for the corresponding third patch on linux kernel side to be merged.
https://lore.kernel.org/xen-devel/20240607075109.126277-4-Jiqian.Chen@amd.com/
---
v13->v15 changes:
Add "Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>"

v12->v13 changes:
Rename the function xc_physdev_gsi_from_pcidev to xc_pcidev_get_gsi to avoid confusion with physdev namesapce.
Move the implementation of xc_pcidev_get_gsi into xc_linux.c.
Directly use xencall_fd(xch->xcall) in the function xc_pcidev_get_gsi instead of opening "privcmd".

v11->v12 changes:
Nothing.

v10->v11 changes:
Patch#4 of v10, directly open "/dev/xen/privcmd" in the function xc_physdev_gsi_from_dev instead of adding unnecessary functions to libxencall.
Change the type of gsi in the structure privcmd_gsi_from_dev from int to u32.

v9->v10 changes:
Extract the implementation of xc_physdev_gsi_from_dev to be a new patch.
---
 tools/include/xen-sys/Linux/privcmd.h |  7 +++++++
 tools/include/xenctrl.h               |  2 ++
 tools/libs/ctrl/xc_freebsd.c          |  6 ++++++
 tools/libs/ctrl/xc_linux.c            | 20 ++++++++++++++++++++
 tools/libs/ctrl/xc_minios.c           |  6 ++++++
 tools/libs/ctrl/xc_netbsd.c           |  6 ++++++
 tools/libs/ctrl/xc_solaris.c          |  6 ++++++
 7 files changed, 53 insertions(+)

Comments

Jan Beulich Sept. 11, 2024, 10:49 a.m. UTC | #1
On 11.09.2024 08:58, Jiqian Chen wrote:
> On PVH dom0, when passthrough a device to domU, QEMU and xl tools
> want to use gsi number to do pirq mapping, see QEMU code
> xen_pt_realize->xc_physdev_map_pirq, and xl code
> pci_add_dm_done->xc_physdev_map_pirq, but in current codes, the gsi
> number is got from file /sys/bus/pci/devices/<sbdf>/irq, that is
> wrong, because irq is not equal with gsi, they are in different
> spaces, so pirq mapping fails.
> 
> And in current codes, there is no method to get gsi for userspace.
> For above purpose, add new function to get gsi, and the
> corresponding ioctl is implemented on linux kernel side.
> 
> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
> Signed-off-by: Huang Rui <ray.huang@amd.com>
> Signed-off-by: Chen Jiqian <Jiqian.Chen@amd.com>
> Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
> ---
> RFC: it needs to wait for the corresponding third patch on linux kernel side to be merged.
> https://lore.kernel.org/xen-devel/20240607075109.126277-4-Jiqian.Chen@amd.com/

I'm afraid I don't understand this remark: The change here (and similarly
patch 4) ought to be independent of when the kernel change goes in. After
all the libraries need to work on older Linux as well. Please clarify.

Jan
Jan Beulich Sept. 11, 2024, 10:51 a.m. UTC | #2
On 11.09.2024 12:49, Jan Beulich wrote:
> On 11.09.2024 08:58, Jiqian Chen wrote:
>> On PVH dom0, when passthrough a device to domU, QEMU and xl tools
>> want to use gsi number to do pirq mapping, see QEMU code
>> xen_pt_realize->xc_physdev_map_pirq, and xl code
>> pci_add_dm_done->xc_physdev_map_pirq, but in current codes, the gsi
>> number is got from file /sys/bus/pci/devices/<sbdf>/irq, that is
>> wrong, because irq is not equal with gsi, they are in different
>> spaces, so pirq mapping fails.
>>
>> And in current codes, there is no method to get gsi for userspace.
>> For above purpose, add new function to get gsi, and the
>> corresponding ioctl is implemented on linux kernel side.
>>
>> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
>> Signed-off-by: Huang Rui <ray.huang@amd.com>
>> Signed-off-by: Chen Jiqian <Jiqian.Chen@amd.com>
>> Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
>> ---
>> RFC: it needs to wait for the corresponding third patch on linux kernel side to be merged.
>> https://lore.kernel.org/xen-devel/20240607075109.126277-4-Jiqian.Chen@amd.com/
> 
> I'm afraid I don't understand this remark: The change here (and similarly
> patch 4) ought to be independent of when the kernel change goes in. After
> all the libraries need to work on older Linux as well. Please clarify.

Hmm, maybe for this patch the dependency is for the new IOCTL as an
interface to be accepted. That's fine a dependency of course. Yet then
why the same remark in patch 4?

Jan
Chen, Jiqian Sept. 12, 2024, 2:01 a.m. UTC | #3
On 2024/9/11 18:51, Jan Beulich wrote:
> On 11.09.2024 12:49, Jan Beulich wrote:
>> On 11.09.2024 08:58, Jiqian Chen wrote:
>>> On PVH dom0, when passthrough a device to domU, QEMU and xl tools
>>> want to use gsi number to do pirq mapping, see QEMU code
>>> xen_pt_realize->xc_physdev_map_pirq, and xl code
>>> pci_add_dm_done->xc_physdev_map_pirq, but in current codes, the gsi
>>> number is got from file /sys/bus/pci/devices/<sbdf>/irq, that is
>>> wrong, because irq is not equal with gsi, they are in different
>>> spaces, so pirq mapping fails.
>>>
>>> And in current codes, there is no method to get gsi for userspace.
>>> For above purpose, add new function to get gsi, and the
>>> corresponding ioctl is implemented on linux kernel side.
>>>
>>> Signed-off-by: Jiqian Chen <Jiqian.Chen@amd.com>
>>> Signed-off-by: Huang Rui <ray.huang@amd.com>
>>> Signed-off-by: Chen Jiqian <Jiqian.Chen@amd.com>
>>> Reviewed-by: Anthony PERARD <anthony.perard@vates.tech>
>>> ---
>>> RFC: it needs to wait for the corresponding third patch on linux kernel side to be merged.
>>> https://lore.kernel.org/xen-devel/20240607075109.126277-4-Jiqian.Chen@amd.com/
>>
>> I'm afraid I don't understand this remark: The change here (and similarly
>> patch 4) ought to be independent of when the kernel change goes in. After
>> all the libraries need to work on older Linux as well. Please clarify.
> 
> Hmm, maybe for this patch the dependency is for the new IOCTL as an
> interface to be accepted. That's fine a dependency of course. Yet then
> why the same remark in patch 4?
Yes, patch#3 depends on the new IOCTL on the kernel side.
Patch#4 uses the new function of patch#3 and new hypercall of patch#2, it depends on patch#2/3, so patch#4 also depends on the patches on the kernel side.
And the kernel patches are too old, I will send a new version this week.

> 
> Jan
diff mbox series

Patch

diff --git a/tools/include/xen-sys/Linux/privcmd.h b/tools/include/xen-sys/Linux/privcmd.h
index bc60e8fd55eb..607dfa2287bc 100644
--- a/tools/include/xen-sys/Linux/privcmd.h
+++ b/tools/include/xen-sys/Linux/privcmd.h
@@ -95,6 +95,11 @@  typedef struct privcmd_mmap_resource {
 	__u64 addr;
 } privcmd_mmap_resource_t;
 
+typedef struct privcmd_pcidev_get_gsi {
+	__u32 sbdf;
+	__u32 gsi;
+} privcmd_pcidev_get_gsi_t;
+
 /*
  * @cmd: IOCTL_PRIVCMD_HYPERCALL
  * @arg: &privcmd_hypercall_t
@@ -114,6 +119,8 @@  typedef struct privcmd_mmap_resource {
 	_IOC(_IOC_NONE, 'P', 6, sizeof(domid_t))
 #define IOCTL_PRIVCMD_MMAP_RESOURCE				\
 	_IOC(_IOC_NONE, 'P', 7, sizeof(privcmd_mmap_resource_t))
+#define IOCTL_PRIVCMD_PCIDEV_GET_GSI			\
+	_IOC(_IOC_NONE, 'P', 10, sizeof(privcmd_pcidev_get_gsi_t))
 #define IOCTL_PRIVCMD_UNIMPLEMENTED				\
 	_IOC(_IOC_NONE, 'P', 0xFF, 0)
 
diff --git a/tools/include/xenctrl.h b/tools/include/xenctrl.h
index 2c4608c09ab0..924f9a35f790 100644
--- a/tools/include/xenctrl.h
+++ b/tools/include/xenctrl.h
@@ -1642,6 +1642,8 @@  int xc_physdev_unmap_pirq(xc_interface *xch,
                           uint32_t domid,
                           int pirq);
 
+int xc_pcidev_get_gsi(xc_interface *xch, uint32_t sbdf);
+
 /*
  *  LOGGING AND ERROR REPORTING
  */
diff --git a/tools/libs/ctrl/xc_freebsd.c b/tools/libs/ctrl/xc_freebsd.c
index 9dd48a3a08bb..9019fc663361 100644
--- a/tools/libs/ctrl/xc_freebsd.c
+++ b/tools/libs/ctrl/xc_freebsd.c
@@ -60,6 +60,12 @@  void *xc_memalign(xc_interface *xch, size_t alignment, size_t size)
     return ptr;
 }
 
+int xc_pcidev_get_gsi(xc_interface *xch, uint32_t sbdf)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/ctrl/xc_linux.c b/tools/libs/ctrl/xc_linux.c
index c67c71c08be3..92591e49a1c8 100644
--- a/tools/libs/ctrl/xc_linux.c
+++ b/tools/libs/ctrl/xc_linux.c
@@ -66,6 +66,26 @@  void *xc_memalign(xc_interface *xch, size_t alignment, size_t size)
     return ptr;
 }
 
+int xc_pcidev_get_gsi(xc_interface *xch, uint32_t sbdf)
+{
+    int ret;
+    privcmd_pcidev_get_gsi_t dev_gsi = {
+        .sbdf = sbdf,
+        .gsi = 0,
+    };
+
+    ret = ioctl(xencall_fd(xch->xcall),
+                IOCTL_PRIVCMD_PCIDEV_GET_GSI, &dev_gsi);
+
+    if (ret < 0) {
+        PERROR("Failed to get gsi from dev");
+    } else {
+        ret = dev_gsi.gsi;
+    }
+
+    return ret;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/ctrl/xc_minios.c b/tools/libs/ctrl/xc_minios.c
index 3dea7a78a576..462af827b33c 100644
--- a/tools/libs/ctrl/xc_minios.c
+++ b/tools/libs/ctrl/xc_minios.c
@@ -47,6 +47,12 @@  void *xc_memalign(xc_interface *xch, size_t alignment, size_t size)
     return memalign(alignment, size);
 }
 
+int xc_pcidev_get_gsi(xc_interface *xch, uint32_t sbdf)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/ctrl/xc_netbsd.c b/tools/libs/ctrl/xc_netbsd.c
index 31979937621e..1318d4d90608 100644
--- a/tools/libs/ctrl/xc_netbsd.c
+++ b/tools/libs/ctrl/xc_netbsd.c
@@ -63,6 +63,12 @@  void *xc_memalign(xc_interface *xch, size_t alignment, size_t size)
     return valloc(size);
 }
 
+int xc_pcidev_get_gsi(xc_interface *xch, uint32_t sbdf)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
 /*
  * Local variables:
  * mode: C
diff --git a/tools/libs/ctrl/xc_solaris.c b/tools/libs/ctrl/xc_solaris.c
index 5128f3f0f490..049e28d55ccd 100644
--- a/tools/libs/ctrl/xc_solaris.c
+++ b/tools/libs/ctrl/xc_solaris.c
@@ -32,6 +32,12 @@  void *xc_memalign(xc_interface *xch, size_t alignment, size_t size)
     return memalign(alignment, size);
 }
 
+int xc_pcidev_get_gsi(xc_interface *xch, uint32_t sbdf)
+{
+    errno = ENOSYS;
+    return -1;
+}
+
 /*
  * Local variables:
  * mode: C