horms@vergenet.net
2009-Dec-31 08:10 UTC
[Xen-devel] [patch 0/2] qemu-xen: pass-through: always use hw intx
pass-through: always use hw intx and always get it from the same place The assumption that function zero always uses INTA tuns out not to be true in the wild. This leaves us with three options. 1) Always use INTA This was the case before multi-function pass-through was possible. But with the advent of multi-function pass-through this may lead to excessive virtual GSI sharing. 2) Fix emulation to use INTA for function zero 3) Always use the hardware value for INTx There doesn''t seem to be much between 2) and 3) but the latter seems slightly cleaner so I advocate that approach. _______________________________________________ Xen-devel mailing list Xen-devel@lists.xensource.com http://lists.xensource.com/xen-devel
horms@vergenet.net
2009-Dec-31 08:10 UTC
[Xen-devel] [patch 1/2] qemu-xen: pass-through: move pci_read_intx() and pci_intx()
Move pci_read_intx() and pci_intx() to above pt_irqpin_reg_init().
This is requred for a subsequent patch where pt_irqpin_reg_init()
calls pci_read_intx().
Cc: Tom Rotenberg <tom.rotenberg@gmail.com>
Cc: Edwin Zhai <edwin.zhai@intel.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Index: ioemu-remote/hw/pass-through.c
==================================================================---
ioemu-remote.orig/hw/pass-through.c 2009-12-31 17:04:08.000000000 +0900
+++ ioemu-remote/hw/pass-through.c 2009-12-31 17:07:22.000000000 +0900
@@ -1021,6 +1021,64 @@ int bdf_to_devfn(char *bdf_str)
return -1;
}
+/* The PCI Local Bus Specification, Rev. 3.0,
+ * Section 6.2.4 Miscellaneous Registers, pp 223
+ * outlines 5 valid values for the intertupt pin (intx).
+ * 0: For devices (or device functions) that don''t use an interrupt
in
+ * 1: INTA#
+ * 2: INTB#
+ * 3: INTC#
+ * 4: INTD#
+ *
+ * Xen uses the following 4 values for intx
+ * 0: INTA#
+ * 1: INTB#
+ * 2: INTC#
+ * 3: INTD#
+ *
+ * Observing that these list of values are not the same, pci_read_intx()
+ * uses the following mapping from hw to xen values.
+ * This seems to reflect the current usage within Xen.
+ *
+ * PCI hardware | Xen | Notes
+ * ----------------+-----+----------------------------------------------------
+ * 0 | 0 | No interrupt
+ * 1 | 0 | INTA#
+ * 2 | 1 | INTB#
+ * 3 | 2 | INTC#
+ * 4 | 3 | INTD#
+ * any other value | 0 | This should never happen, log error message
+ */
+static uint8_t pci_read_intx(struct pt_dev *ptdev)
+{
+ uint8_t r_val = pci_read_byte(ptdev->pci_dev, PCI_INTERRUPT_PIN);
+
+ PT_LOG("intx=%i\n", r_val);
+ if (r_val < 1 || r_val > 4)
+ {
+ PT_LOG("Interrupt pin read from hardware is out of range: "
+ "value=%i, acceptable range is 1 - 4\n", r_val);
+ r_val = 0;
+ }
+ else
+ {
+ r_val -= 1;
+ }
+
+ return r_val;
+}
+
+/*
+ * For virtual function 0, always use INTA#,
+ * otherwise use the hardware value
+ */
+uint8_t pci_intx(struct pt_dev *ptdev)
+{
+ if (!PCI_FUNC(ptdev->dev.devfn))
+ return 0;
+ return pci_read_intx(ptdev);
+}
+
/* Being called each time a mmio region has been updated */
static void pt_iomem_map(PCIDevice *d, int i, uint32_t e_phys, uint32_t e_size,
int type)
@@ -4470,61 +4528,3 @@ int pt_init(PCIBus *e_bus)
return 0;
}
-
-/* The PCI Local Bus Specification, Rev. 3.0,
- * Section 6.2.4 Miscellaneous Registers, pp 223
- * outlines 5 valid values for the intertupt pin (intx).
- * 0: For devices (or device functions) that don''t use an interrupt
in
- * 1: INTA#
- * 2: INTB#
- * 3: INTC#
- * 4: INTD#
- *
- * Xen uses the following 4 values for intx
- * 0: INTA#
- * 1: INTB#
- * 2: INTC#
- * 3: INTD#
- *
- * Observing that these list of values are not the same, pci_read_intx()
- * uses the following mapping from hw to xen values.
- * This seems to reflect the current usage within Xen.
- *
- * PCI hardware | Xen | Notes
- * ----------------+-----+----------------------------------------------------
- * 0 | 0 | No interrupt
- * 1 | 0 | INTA#
- * 2 | 1 | INTB#
- * 3 | 2 | INTC#
- * 4 | 3 | INTD#
- * any other value | 0 | This should never happen, log error message
- */
-static uint8_t pci_read_intx(struct pt_dev *ptdev)
-{
- uint8_t r_val = pci_read_byte(ptdev->pci_dev, PCI_INTERRUPT_PIN);
-
- PT_LOG("intx=%i\n", r_val);
- if (r_val < 1 || r_val > 4)
- {
- PT_LOG("Interrupt pin read from hardware is out of range: "
- "value=%i, acceptable range is 1 - 4\n", r_val);
- r_val = 0;
- }
- else
- {
- r_val -= 1;
- }
-
- return r_val;
-}
-
-/*
- * For virtual function 0, always use INTA#,
- * otherwise use the hardware value
- */
-uint8_t pci_intx(struct pt_dev *ptdev)
-{
- if (!PCI_FUNC(ptdev->dev.devfn))
- return 0;
- return pci_read_intx(ptdev);
-}
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horms@vergenet.net
2009-Dec-31 08:10 UTC
[Xen-devel] [patch 2/2] qemu-xen: pass-through: always use hw intx
pass-through: always use hw intx and always get it from the same place
The assumption that function zero always uses INTA tuns out not
to be true in the wild. This leaves us with three options.
1) Always use INTA
This was the case before multi-function pass-through was possible.
But with the advent of multi-function pass-through this may lead
to excessive virtual GSI sharing.
2) Fix emulation to use INTA for function zero
3) Always use the hardware value for INTx
There doesn''t seem to be much between 2) and 3) but the latter seems
slightly cleaner so I advocate that approach.
Cc: Tom Rotenberg <tom.rotenberg@gmail.com>
Cc: Edwin Zhai <edwin.zhai@intel.com>
Signed-off-by: Simon Horman <horms@verge.net.au>
Index: ioemu-remote/hw/pass-through.c
==================================================================---
ioemu-remote.orig/hw/pass-through.c 2009-12-31 17:04:46.000000000 +0900
+++ ioemu-remote/hw/pass-through.c 2009-12-31 17:06:52.000000000 +0900
@@ -1021,6 +1021,11 @@ int bdf_to_devfn(char *bdf_str)
return -1;
}
+static uint8_t pci_read_intx(struct pt_dev *ptdev)
+{
+ return pci_read_byte(ptdev->pci_dev, PCI_INTERRUPT_PIN);
+}
+
/* The PCI Local Bus Specification, Rev. 3.0,
* Section 6.2.4 Miscellaneous Registers, pp 223
* outlines 5 valid values for the intertupt pin (intx).
@@ -1049,9 +1054,9 @@ int bdf_to_devfn(char *bdf_str)
* 4 | 3 | INTD#
* any other value | 0 | This should never happen, log error message
*/
-static uint8_t pci_read_intx(struct pt_dev *ptdev)
+uint8_t pci_intx(struct pt_dev *ptdev)
{
- uint8_t r_val = pci_read_byte(ptdev->pci_dev, PCI_INTERRUPT_PIN);
+ uint8_t r_val = pci_read_intx(ptdev);
PT_LOG("intx=%i\n", r_val);
if (r_val < 1 || r_val > 4)
@@ -1068,17 +1073,6 @@ static uint8_t pci_read_intx(struct pt_d
return r_val;
}
-/*
- * For virtual function 0, always use INTA#,
- * otherwise use the hardware value
- */
-uint8_t pci_intx(struct pt_dev *ptdev)
-{
- if (!PCI_FUNC(ptdev->dev.devfn))
- return 0;
- return pci_read_intx(ptdev);
-}
-
/* Being called each time a mmio region has been updated */
static void pt_iomem_map(PCIDevice *d, int i, uint32_t e_phys, uint32_t e_size,
int type)
@@ -2768,7 +2762,7 @@ static uint32_t pt_status_reg_init(struc
static uint32_t pt_irqpin_reg_init(struct pt_dev *ptdev,
struct pt_reg_info_tbl *reg, uint32_t real_offset)
{
- return ptdev->dev.config[real_offset];
+ return pci_read_intx(ptdev);
}
/* initialize BAR */
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