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[Qemu-devel] [PATCH v2] pc: acpi: fix pvpanic for buggy guests
From: |
Radim Krčmář |
Subject: |
[Qemu-devel] [PATCH v2] pc: acpi: fix pvpanic for buggy guests |
Date: |
Fri, 29 May 2015 21:57:32 +0200 |
In the old times, we always had pvpanic in ACPI and a _STA method told
the guest not to use it. Automatic generation dropped the _STA method
as the specification says that missing _STA means enabled and working.
Some guests (Linux) had buggy drivers and this change made them unable
to utilize pvpanic.
A Linux patch is posted as well, but I think it's worth to make pvpanic
useable on old guests at the price of three lines and few bytes of SSDT.
The old _STA method was
Method (_STA, 0, NotSerialized) {
Store (PEST, Local0)
If (LEqual (Local0, Zero)) {
Return (Zero) }
Else {
Return (0x0F) }}
Igor pointed out that we don't need to use a method to return a constant
and that 0xB (don't show in UI) is the common definition now.
Also, the device used to be PEVT. (PEVT as in "panic event"?)
Signed-off-by: Radim Krčmář <address@hidden>
---
v2: Use name_decl instead of method and return 0xb [Igor]
Improve subject an commit message.
Btw. I dislike the comment, so I've added a personal TODO to write 0xB
in a programmer-friendly way.
hw/i386/acpi-build.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 73259e729b9f..50f4951ec79e 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -733,7 +733,7 @@ build_ssdt(GArray *table_data, GArray *linker,
if (misc->pvpanic_port) {
scope = aml_scope("\\_SB.PCI0.ISA");
- dev = aml_device("PEVR");
+ dev = aml_device("PEVT");
aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0001")));
crs = aml_resource_template();
@@ -748,6 +748,9 @@ build_ssdt(GArray *table_data, GArray *linker,
aml_append(field, aml_named_field("PEPT", 8));
aml_append(dev, field);
+ /* device present, functioning, decoding, not shown in UI */
+ aml_append(dev, aml_name_decl("_STA", aml_int(0xB)));
+
method = aml_method("RDPT", 0);
aml_append(method, aml_store(aml_name("PEPT"), aml_local(0)));
aml_append(method, aml_return(aml_local(0)));
--
2.4.2
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