hw/i386/acpi-build: Return a pre-computed _PRT table
When qemu runs without kvm acceleration the ACPI executions take a great
amount of time. If they take more than the default time (30sec), the
ACPI calls fail and the system might not behave correctly.
Now the _PRT table is computed on the fly. We can drastically reduce the
execution of the _PRT method if we return a pre-computed table.
Without this patch:
[ 51.343484] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[ 51.527032] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[ 51.530049] virtio-pci 0000:00:02.0: can't derive routing for PCI INT A
[ 51.530797] virtio-pci 0000:00:02.0: PCI INT A: no GSI
[ 81.922901] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[ 82.103534] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[ 82.106088] virtio-pci 0000:00:04.0: can't derive routing for PCI INT A
[ 82.106761] virtio-pci 0000:00:04.0: PCI INT A: no GSI
[ 112.192568] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[ 112.486687] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[ 112.489554] virtio-pci 0000:00:05.0: can't derive routing for PCI INT A
[ 112.490027] virtio-pci 0000:00:05.0: PCI INT A: no GSI
[ 142.559448] ACPI Error: Aborting method \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/psparse-529)
[ 142.718596] ACPI Error: Method execution failed \_SB.PCI0._PRT due to previous error (AE_AML_LOOP_TIMEOUT) (20230628/uteval-68)
[ 142.722889] virtio-pci 0000:00:06.0: can't derive routing for PCI INT A
[ 142.724578] virtio-pci 0000:00:06.0: PCI INT A: no GSI
With this patch:
[ 22.938076] ACPI: \_SB_.LNKB: Enabled at IRQ 10
[ 24.214002] ACPI: \_SB_.LNKD: Enabled at IRQ 11
[ 25.465170] ACPI: \_SB_.LNKA: Enabled at IRQ 10
[ 27.944920] ACPI: \_SB_.LNKC: Enabled at IRQ 11
ACPI disassembly:
Scope (PCI0)
{
Method (_PRT, 0, NotSerialized) // _PRT: PCI Routing Table
{
Return (Package (0x80)
{
Package (0x04)
{
0xFFFF,
Zero,
LNKD,
Zero
},
Package (0x04)
{
0xFFFF,
One,
LNKA,
Zero
},
Package (0x04)
{
0xFFFF,
0x02,
LNKB,
Zero
},
Package (0x04)
{
0xFFFF,
0x03,
LNKC,
Zero
},
Package (0x04)
{
0x0001FFFF,
Zero,
LNKS,
Zero
},
Context: https://lore.kernel.org/virtualization/20240417145544.38d7b482@imammedo.users.ipa.redhat.com/T/#t
Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Igor Mammedov <imammedo@redhat.com>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20240814115736.1580337-3-ribalda@chromium.org>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 5d4bd2b..4967aa7 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -724,120 +724,44 @@
return method;
}
-/**
- * build_prt_entry:
- * @link_name: link name for PCI route entry
- *
- * build AML package containing a PCI route entry for @link_name
- */
-static Aml *build_prt_entry(const char *link_name)
-{
- Aml *a_zero = aml_int(0);
- Aml *pkg = aml_package(4);
- aml_append(pkg, a_zero);
- aml_append(pkg, a_zero);
- aml_append(pkg, aml_name("%s", link_name));
- aml_append(pkg, a_zero);
- return pkg;
-}
-
/*
- * initialize_route - Initialize the interrupt routing rule
- * through a specific LINK:
- * if (lnk_idx == idx)
- * route using link 'link_name'
- */
-static Aml *initialize_route(Aml *route, const char *link_name,
- Aml *lnk_idx, int idx)
-{
- Aml *if_ctx = aml_if(aml_equal(lnk_idx, aml_int(idx)));
- Aml *pkg = build_prt_entry(link_name);
-
- aml_append(if_ctx, aml_store(pkg, route));
-
- return if_ctx;
-}
-
-/*
- * build_prt - Define interrupt rounting rules
+ * build_prt - Define interrupt routing rules
*
* Returns an array of 128 routes, one for each device,
* based on device location.
* The main goal is to equally distribute the interrupts
* over the 4 existing ACPI links (works only for i440fx).
- * The hash function is (slot + pin) & 3 -> "LNK[D|A|B|C]".
+ * The hash function is: (slot + pin) & 3 -> "LNK[D|A|B|C]".
*
*/
static Aml *build_prt(bool is_pci0_prt)
{
- Aml *method, *while_ctx, *pin, *res;
+ const int nroutes = 128;
+ Aml *rt_pkg, *method;
+ int pin;
method = aml_method("_PRT", 0, AML_NOTSERIALIZED);
- res = aml_local(0);
- pin = aml_local(1);
- aml_append(method, aml_store(aml_package(128), res));
- aml_append(method, aml_store(aml_int(0), pin));
+ rt_pkg = aml_varpackage(nroutes);
- /* while (pin < 128) */
- while_ctx = aml_while(aml_lless(pin, aml_int(128)));
- {
- Aml *slot = aml_local(2);
- Aml *lnk_idx = aml_local(3);
- Aml *route = aml_local(4);
+ for (pin = 0; pin < nroutes; pin++) {
+ Aml *pkg = aml_package(4);
+ int slot = pin >> 2;
- /* slot = pin >> 2 */
- aml_append(while_ctx,
- aml_store(aml_shiftright(pin, aml_int(2), NULL), slot));
- /* lnk_idx = (slot + pin) & 3 */
- aml_append(while_ctx,
- aml_store(aml_and(aml_add(pin, slot, NULL), aml_int(3), NULL),
- lnk_idx));
-
- /* route[2] = "LNK[D|A|B|C]", selection based on pin % 3 */
- aml_append(while_ctx, initialize_route(route, "LNKD", lnk_idx, 0));
- if (is_pci0_prt) {
- Aml *if_device_1, *if_pin_4, *else_pin_4;
-
- /* device 1 is the power-management device, needs SCI */
- if_device_1 = aml_if(aml_equal(lnk_idx, aml_int(1)));
- {
- if_pin_4 = aml_if(aml_equal(pin, aml_int(4)));
- {
- aml_append(if_pin_4,
- aml_store(build_prt_entry("LNKS"), route));
- }
- aml_append(if_device_1, if_pin_4);
- else_pin_4 = aml_else();
- {
- aml_append(else_pin_4,
- aml_store(build_prt_entry("LNKA"), route));
- }
- aml_append(if_device_1, else_pin_4);
- }
- aml_append(while_ctx, if_device_1);
+ aml_append(pkg, aml_int((slot << 16) | 0xFFFF));
+ aml_append(pkg, aml_int(pin & 3));
+ /* device 1 is the power-management device, needs SCI */
+ if (is_pci0_prt && pin == 4) {
+ aml_append(pkg, aml_name("%s", "LNKS"));
} else {
- aml_append(while_ctx, initialize_route(route, "LNKA", lnk_idx, 1));
+ static const char link_name[][5] = {"LNKD", "LNKA", "LNKB", "LNKC"};
+ int hash = (slot + pin) & 3;
+ aml_append(pkg, aml_name("%s", link_name[hash]));
}
- aml_append(while_ctx, initialize_route(route, "LNKB", lnk_idx, 2));
- aml_append(while_ctx, initialize_route(route, "LNKC", lnk_idx, 3));
-
- /* route[0] = 0x[slot]FFFF */
- aml_append(while_ctx,
- aml_store(aml_or(aml_shiftleft(slot, aml_int(16)), aml_int(0xFFFF),
- NULL),
- aml_index(route, aml_int(0))));
- /* route[1] = pin & 3 */
- aml_append(while_ctx,
- aml_store(aml_and(pin, aml_int(3), NULL),
- aml_index(route, aml_int(1))));
- /* res[pin] = route */
- aml_append(while_ctx, aml_store(route, aml_index(res, pin)));
- /* pin++ */
- aml_append(while_ctx, aml_increment(pin));
+ aml_append(pkg, aml_int(0));
+ aml_append(rt_pkg, pkg);
}
- aml_append(method, while_ctx);
- /* return res*/
- aml_append(method, aml_return(res));
+
+ aml_append(method, aml_return(rt_pkg));
return method;
}
