From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:49594) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YyQPk-0004Hi-PV for qemu-devel@nongnu.org; Fri, 29 May 2015 15:57:57 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1YyQPf-000534-Pk for qemu-devel@nongnu.org; Fri, 29 May 2015 15:57:56 -0400 Received: from mx1.redhat.com ([209.132.183.28]:52202) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1YyQPf-00052w-KM for qemu-devel@nongnu.org; Fri, 29 May 2015 15:57:51 -0400 From: =?UTF-8?q?Radim=20Kr=C4=8Dm=C3=A1=C5=99?= Date: Fri, 29 May 2015 21:57:32 +0200 Message-Id: <1432929452-30799-1-git-send-email-rkrcmar@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Subject: [Qemu-devel] [PATCH v2] pc: acpi: fix pvpanic for buggy guests List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: imammedo@redhat.com, rth@twiddle.net, mst@redhat.com, pbonzini@redhat.com 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 Kr=C4=8Dm=C3=A1=C5=99 --- v2: Use name_decl instead of method and return 0xb [Igor] Improve subject an commit message. =20 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 =3D aml_scope("\\_SB.PCI0.ISA"); =20 - dev =3D aml_device("PEVR"); + dev =3D aml_device("PEVT"); aml_append(dev, aml_name_decl("_HID", aml_string("QEMU0001"))); =20 crs =3D 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); =20 + /* device present, functioning, decoding, not shown in UI */ + aml_append(dev, aml_name_decl("_STA", aml_int(0xB))); + method =3D aml_method("RDPT", 0); aml_append(method, aml_store(aml_name("PEPT"), aml_local(0))); aml_append(method, aml_return(aml_local(0))); --=20 2.4.2