From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45591) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aH7U7-0004Qq-ST for qemu-devel@nongnu.org; Thu, 07 Jan 2016 05:08:00 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aH7U3-0000Md-Rh for qemu-devel@nongnu.org; Thu, 07 Jan 2016 05:07:59 -0500 Received: from mail-wm0-x22c.google.com ([2a00:1450:400c:c09::22c]:34230) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aH7U3-0000MX-KW for qemu-devel@nongnu.org; Thu, 07 Jan 2016 05:07:55 -0500 Received: by mail-wm0-x22c.google.com with SMTP id u188so91693985wmu.1 for ; Thu, 07 Jan 2016 02:07:55 -0800 (PST) Sender: Paolo Bonzini References: <1449768334-12782-1-git-send-email-lersek@redhat.com> <20151210195336.459c0c64@igors-macbook-pro.local> <568AA993.2090006@redhat.com> From: Paolo Bonzini Message-ID: <568E38F2.1010507@redhat.com> Date: Thu, 7 Jan 2016 11:07:46 +0100 MIME-Version: 1.0 In-Reply-To: <568AA993.2090006@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 8bit Subject: Re: [Qemu-devel] [PATCH] hw/i386: fill in the CENTURY field of the FADT (FACP) ACPI table List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Laszlo Ersek , Igor Mammedov , Eduardo Habkost , "Michael S. Tsirkin" Cc: Ruiyu Ni , qemu-devel@nongnu.org, Richard Henderson On 04/01/2016 18:19, Laszlo Ersek wrote: > On 12/10/15 19:53, Igor Mammedov wrote: >> On Thu, 10 Dec 2015 18:25:34 +0100 >> Laszlo Ersek wrote: >> >>> The ACPI specification (minimally versions 1.0b through 6.0) define >>> the FADT.CENTURY field as: >>> >>> The RTC CMOS RAM index to the century of data value (hundred and >>> thousand year decimals). If this field contains a zero, then the RTC >>> centenary feature is not supported. If this field has a non-zero >>> value, then this field contains an index into RTC RAM space that OSPM >>> can use to program the centenary field. >>> >>> The x86 targets generate ACPI payload, emulate an RTC >>> (CONFIG_MC146818RTC), and that RTC supports the "centenary >>> feature" (see occurrences of RTC_CENTURY in cmos_ioport_write() and >>> cmos_ioport_read() in "hw/timer/mc146818rtc.c".) >>> >>> However, FADT.CENTURY is left at zero currently: >>> >>> [06Ch 0108 1] RTC Century Index : 00 >>> >>> which -- according to analysis done by Ruiyu Ni at Intel -- should >>> cause Linux and Windows 8+ to think the RTC centenary feature is >>> unavailable, and cause Windows 7 to (incorrectly) assume that the >>> offset to use is constant 0x32. (0x32 happens to be the right value >>> on QEMU, but Windows 7 is wrong to assume anything at all). >>> >>> Exposing the right nonzero offset in FADT.CENTURY informs Linux and >>> Windows 8+ about the right capabilities of the hardware, plus it >>> retrofits our FADT to Windows 7's behavior. >>> >>> Regression tested with the following guests (all UEFI installs): >>> - i386 Q35: Fedora 21 ("Fedlet" edition) >>> - x86_64: >>> - i440fx: >>> - Fedora 21 >>> - RHEL 6 and 7 >>> - Windows 7 and 10 >>> - Windows Server 2008 R2 and 2012 R2 >>> - Q35: >>> - Fedora 22 >>> - Windows 8.1 >>> >>> Cc: "Michael S. Tsirkin" (supporter:ACPI/SMBIOS) >>> Cc: Igor Mammedov (supporter:ACPI/SMBIOS) >>> Cc: Paolo Bonzini (maintainer:X86) >>> Cc: Richard Henderson (maintainer:X86) >>> Cc: Eduardo Habkost (maintainer:X86) >>> Cc: Ruiyu Ni >>> Signed-off-by: Laszlo Ersek >>> --- >>> hw/i386/acpi-build.c | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c >>> index 95e0c65..c5e6c4b 100644 >>> --- a/hw/i386/acpi-build.c >>> +++ b/hw/i386/acpi-build.c >>> @@ -42,6 +42,7 @@ >>> #include "sysemu/tpm.h" >>> #include "hw/acpi/tpm.h" >>> #include "sysemu/tpm_backend.h" >>> +#include "hw/timer/mc146818rtc_regs.h" >>> >>> /* Supported chipsets: */ >>> #include "hw/acpi/piix4.h" >>> @@ -334,6 +335,7 @@ static void fadt_setup(AcpiFadtDescriptorRev1 >>> *fadt, AcpiPmInfo *pm) if (max_cpus > 8) { >>> fadt->flags |= cpu_to_le32(1 << >>> ACPI_FADT_F_FORCE_APIC_CLUSTER_MODEL); } >>> + fadt->century = RTC_CENTURY; >>> } >>> >>> >> >> Reviewed-by: Igor Mammedov >> > > Thanks. > > Can someone please pick up this patch? It should probably go in through Michael's tree, but I've queued it too so that it isn't forgotten. Paolo