diff mbox

hw/i386: fill in the CENTURY field of the FADT (FACP) ACPI table

Message ID 1449768334-12782-1-git-send-email-lersek@redhat.com
State Accepted
Commit f070efa8d9359c01e8ba64f53ff3c730a362027a
Headers show

Commit Message

Laszlo Ersek Dec. 10, 2015, 5:25 p.m. UTC
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" <mst@redhat.com> (supporter:ACPI/SMBIOS)
Cc: Igor Mammedov <imammedo@redhat.com> (supporter:ACPI/SMBIOS)
Cc: Paolo Bonzini <pbonzini@redhat.com> (maintainer:X86)
Cc: Richard Henderson <rth@twiddle.net> (maintainer:X86)
Cc: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)
Cc: Ruiyu Ni <ruiyu.ni@intel.com>
Signed-off-by: Laszlo Ersek <lersek@redhat.com>

---
 hw/i386/acpi-build.c | 2 ++
 1 file changed, 2 insertions(+)

-- 
1.8.3.1

Comments

Laszlo Ersek Jan. 4, 2016, 5:19 p.m. UTC | #1
On 12/10/15 19:53, Igor Mammedov wrote:
> On Thu, 10 Dec 2015 18:25:34 +0100

> Laszlo Ersek <lersek@redhat.com> 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" <mst@redhat.com> (supporter:ACPI/SMBIOS)

>> Cc: Igor Mammedov <imammedo@redhat.com> (supporter:ACPI/SMBIOS)

>> Cc: Paolo Bonzini <pbonzini@redhat.com> (maintainer:X86)

>> Cc: Richard Henderson <rth@twiddle.net> (maintainer:X86)

>> Cc: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)

>> Cc: Ruiyu Ni <ruiyu.ni@intel.com>

>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

>> ---

>>  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 <imammedo@redhat.com>

> 


Thanks.

Can someone please pick up this patch?

Thanks
Laszlo
Laszlo Ersek Jan. 7, 2016, 5:03 p.m. UTC | #2
On 01/07/16 12:24, Paolo Bonzini wrote:
> 

> 

> On 07/01/2016 12:22, Michael S. Tsirkin wrote:

>> On Thu, Jan 07, 2016 at 11:07:46AM +0100, Paolo Bonzini wrote:

>>>

>>>

>>> 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 <lersek@redhat.com> 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" <mst@redhat.com> (supporter:ACPI/SMBIOS)

>>>>>> Cc: Igor Mammedov <imammedo@redhat.com> (supporter:ACPI/SMBIOS)

>>>>>> Cc: Paolo Bonzini <pbonzini@redhat.com> (maintainer:X86)

>>>>>> Cc: Richard Henderson <rth@twiddle.net> (maintainer:X86)

>>>>>> Cc: Eduardo Habkost <ehabkost@redhat.com> (maintainer:X86)

>>>>>> Cc: Ruiyu Ni <ruiyu.ni@intel.com>

>>>>>> Signed-off-by: Laszlo Ersek <lersek@redhat.com>

>>>>>> ---

>>>>>>  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 <imammedo@redhat.com>

>>>>>

>>>>

>>>> 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

>>

>> Yes - thanks!

>> I picked this up - should I add your Reviewed-by tag?

> 

> Sure!

> 

> Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

> 

> Paolo

> 


Thanks guys.
Laszlo
diff mbox

Patch

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;
 }