From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:33137) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aG8my-0003nJ-Sy for qemu-devel@nongnu.org; Mon, 04 Jan 2016 12:19:26 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1aG8mu-0005Ra-8E for qemu-devel@nongnu.org; Mon, 04 Jan 2016 12:19:24 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34338) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1aG8mu-0005RW-0Y for qemu-devel@nongnu.org; Mon, 04 Jan 2016 12:19:20 -0500 References: <1449768334-12782-1-git-send-email-lersek@redhat.com> <20151210195336.459c0c64@igors-macbook-pro.local> From: Laszlo Ersek Message-ID: <568AA993.2090006@redhat.com> Date: Mon, 4 Jan 2016 18:19:15 +0100 MIME-Version: 1.0 In-Reply-To: <20151210195336.459c0c64@igors-macbook-pro.local> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit 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: Igor Mammedov , Eduardo Habkost , "Michael S. Tsirkin" , Paolo Bonzini Cc: Ruiyu Ni , qemu-devel@nongnu.org, Richard Henderson 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? Thanks Laszlo