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Re: [Qemu-devel] [PATCH] pc: acpi: keep pvpanic backward compatible
From: |
Igor Mammedov |
Subject: |
Re: [Qemu-devel] [PATCH] pc: acpi: keep pvpanic backward compatible |
Date: |
Fri, 29 May 2015 10:51:55 +0200 |
On Wed, 27 May 2015 18:29:17 +0200
Radim Krčmář <address@hidden> wrote:
> In the old times, we always had pvpanic in ACPI and a _STA function told
> the guest not to use it. Now, we only include pvpanic in ACPI if it is
> enabled, so the _STA function is useless from qemu's point of view, but
> guests still want to query availability. Make them happy.
maybe also fix guest's driver not to do since absence of _STA
implies that device is present according to ACPI6.0 6.3.7 _STA
or only fix driver and drop this patch so that QEMU wouldn't carry
useless junk.
>
> This patch extends
> e65bef695441 pc: acpi: fix pvpanic regression
>
> The original _STA method was
> Method (_STA, 0, NotSerialized) {
> Store (PEST, Local0)
> If (LEqual (Local0, Zero)) {
> Return (Zero) }
> Else {
> Return (0x0F) }}
>
> hence we return only 0xf now.
> (Why Linux does '& 0xb' on this result is completely beyond me.)
check _STA related comment in SMC
>
> Also, the device used to be PEVT. (PEVT as in "panic event"?)
>
> Signed-off-by: Radim Krčmář <address@hidden>
> ---
> hw/i386/acpi-build.c | 6 +++++-
> 1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
> index 73259e729b9f..4141c110a8e1 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 +748,10 @@ build_ssdt(GArray *table_data, GArray *linker,
> aml_append(field, aml_named_field("PEPT", 8));
> aml_append(dev, field);
>
> + method = aml_method("_STA", 0);
> + aml_append(method, aml_return(aml_int(0xf)));
> + aml_append(dev, method);
doesn't have to be method,
make it like this:
/* 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)));