On 15/03/2017 15:17, Michael S. Tsirkin wrote: > On Wed, Mar 15, 2017 at 07:20:25PM +1300, Phil Dennis-Jordan wrote: >> This updates the FADT generated for x86/64 machine types from Revision 1 to >> 3. (Based on ACPI standard 2.0 instead of 1.0) As previously, the goal is to >> make running macOS/OS X guests smoother. With a Rev1 FADT, rebooting such a >> guest doesn't work, as the OS uses the reset register information from the >> FADT. Switching to a Rev3 (ACPI 2.0) FADT solves this problem. >> >> The previous discussion of this raised a bunch of points, which I'll >> address/clarify here as well: >> >> 1. No runtime option. The preference was expressed that we try to stay >> backwards-compatible with legacy guests as opposed to adding a runtime >> option for different APCI versions. ACPI 2.0/FADT Rev3 is the minimum >> version required for exposing the reset register, and it is also >> backwards-compatible with 1.0/Rev1, so that seemed a good version to target. >> >> 2. Legacy guest testing. I've tested this successfully (no apparent >> regressions) with: >> * Windows XP x86 (both "pc" and "q35" machine types, the latter using >> -device piix4-ide) >> * Windows 7, both 32-bit and 64-bit editions >> * Windows 10 x64 >> * Fedora 7 x86 Live image >> * Fedora 25 x86_64 Live image >> * Ubuntu 10.04.4 AMD64 Live image >> Any other specific OSes and versions I should check? >> >> >> 3. 64-bit and 32-bit pointer fields. >> >> Only very recent versions of the ACPI spec (6.1 and various errata of 5.1 >> and 6.0) are clear about mutual exclusion of the FADT's 32-bit and 64-bit >> variants of pointers to tables and registers. The 2.0 version simply states >> "This is a required field" for both PM1a_EVT_BLK and X_PM1a_EVT_BLK, for >> example, although it does also state for the former that "This field is >> superseded in ACPI 2.0 by the X_PM1a_EVT_BLK field." No requirement is >> specified explicitly for the DSDT and X_DSDT fields. >> >> In practice, I have found that Windows 10 will fail to boot with a Rev3 FADT >> unless BOTH the 32-bit and 64-bit variants are filled. The exception is >> X_FIRMWARE_CTRL, which is the first to be explicitly marked as mutually >> exclusive with FIRMWARE_CTRL in an ACPI spec - with a preference for >> FIRMWARE_CTRL if the pointer fits in a 32-bit field. Satisfying Windows 10 >> in this way does not contradict the 2.0 specification, and it also complies >> with the 1.0 standard for the fields which Rev1 of the FADT already has, so >> that's what I've gone with in the implementation. >> >> The only problem is that upstream OVMF cannot deal with multiple pointers to >> the same table in the linker commands. This turns out to be a bug in >> OVMF/EDK2[1], and I am submitting a separate patch to EDK2 to fix that >> problem. The fix for a second issue where OVMF would rewrite the FADT so the >> DSDT is erroneously set to 0 has already been upstreamed.[2] I don't see a >> workaround to this other than fixing the OVMF code. >> >> 4. i440FX vs Q35 >> >> Both machine types have the reset register, and it's at the same I/O port. >> To illustrate/document this, the second patch in the series adds a >> build-time assertion that this is indeed so. >> >> Changelog >> ========= >> >> v2 -> v3: >> * I actually completed the changes to the BIOS tables test which were >> required as a result of the FADT struct change. >> >> v1 -> v2: >> * v1 Thread was "[PATCH RFC] acpi: add reset register to fadt" >> * Instead of just adding the reset register, set up a fully standards >> compliant Rev3 FADT. (ACPI 2.0) >> * A compile-time assertion has been added for the PC/Q35 reset register >> equivalence. >> >> >> [1]: https://bugzilla.tianocore.org/show_bug.cgi?id=368 >> [2]: EDK2 commit range e0e1cfcbbb24..198a46d768fb >> >> Phil Dennis-Jordan (2): >> hw/i386: Use Rev3 FADT (ACPI 2.0) instead of Rev1 to improve guest OS >> support. >> hw/i386: Build-time assertion on pc/q35 reset register being >> identical. >> >> hw/i386/acpi-build.c | 35 +++++++++++++++++++-- >> hw/pci-host/piix.c | 6 ---- >> include/hw/acpi/acpi-defs.h | 77 >> +++++++++++++++++++++------------------------ >> include/hw/i386/pc.h | 6 ++++ >> tests/acpi-utils.h | 10 ++++++ >> tests/bios-tables-test.c | 23 +++++++++++--- >> 6 files changed, 102 insertions(+), 55 deletions(-) >> >> -- >> 2.3.2 (Apple Git-55) > > > Looks good to me now. Pls remember to re-post after release > so I can merge.
No need to, I still had it in my inbox so I queued it. Fine by you? Paolo
