From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:45419) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1cTBtW-0004na-DV for qemu-devel@nongnu.org; Mon, 16 Jan 2017 13:20:39 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1cTBtV-0007Nj-DD for qemu-devel@nongnu.org; Mon, 16 Jan 2017 13:20:38 -0500 Received: from mail-ua0-x22f.google.com ([2607:f8b0:400c:c08::22f]:34124) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_128_CBC_SHA1:16) (Exim 4.71) (envelope-from ) id 1cTBtV-0007Nf-8m for qemu-devel@nongnu.org; Mon, 16 Jan 2017 13:20:37 -0500 Received: by mail-ua0-x22f.google.com with SMTP id 35so86853000uak.1 for ; Mon, 16 Jan 2017 10:20:37 -0800 (PST) MIME-Version: 1.0 In-Reply-To: References: <1484328738-21149-1-git-send-email-ard.biesheuvel@linaro.org> From: Peter Maydell Date: Mon, 16 Jan 2017 18:20:16 +0000 Message-ID: Content-Type: text/plain; charset=UTF-8 Subject: Re: [Qemu-devel] [PATCH v2] hw/arm/virt-acpi - reserve ECAM space as PNP0C02 device List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Ard Biesheuvel Cc: QEMU Developers , Graeme Gregory , Al Stone , Leif Lindholm , Andrew Jones On 16 January 2017 at 17:30, Ard Biesheuvel wrote: > On 16 January 2017 at 17:25, Peter Maydell wrote: >> On 13 January 2017 at 17:32, Ard Biesheuvel wrote: >>> Linux for arm64 v4.10 and later will complain if the ECAM config space is >>> not reserved in the ACPI namespace: >>> >>> acpi PNP0A08:00: [Firmware Bug]: ECAM area [mem 0x3f000000-0x3fffffff] not reserved in ACPI namespace >>> >>> The rationale is that OSes that don't consume the MCFG table should still >>> be able to infer that the PCI config space MMIO region is occupied. >>> >>> So update the ACPI table generation routine to add this reservation. >>> >>> Signed-off-by: Ard Biesheuvel >>> --- >>> hw/arm/virt-acpi-build.c | 7 +++++++ >>> 1 file changed, 7 insertions(+) >>> >>> diff --git a/hw/arm/virt-acpi-build.c b/hw/arm/virt-acpi-build.c >>> index 085a61117378..50d52f685f68 100644 >>> --- a/hw/arm/virt-acpi-build.c >>> +++ b/hw/arm/virt-acpi-build.c >>> @@ -310,6 +310,13 @@ static void acpi_dsdt_add_pci(Aml *scope, const MemMapEntry *memmap, >>> Aml *dev_rp0 = aml_device("%s", "RP0"); >>> aml_append(dev_rp0, aml_name_decl("_ADR", aml_int(0))); >>> aml_append(dev, dev_rp0); >>> + >>> + Aml *dev_res0 = aml_device("%s", "RES0"); >>> + aml_append(dev_res0, aml_name_decl("_HID", aml_string("PNP0C02"))); >>> + crs = aml_resource_template(); >>> + aml_append(crs, aml_memory32_fixed(base_ecam, size_ecam, AML_READ_WRITE)); >>> + aml_append(dev_res0, aml_name_decl("_CRS", crs)); >>> + aml_append(dev, dev_res0); >>> aml_append(scope, dev); >>> } >> >> This needs to be controlled via the machine class back-compat >> machinery in hw/arm/virt.c so that it only happens for virt-2.9 >> and later. >> > > Why exactly? Because the "virt-2.8" machine has to present to the guest exactly what "virt" did as of the QEMU 2.8 release, including any bugs or missing things we happened to have in our ACPI tables. This allows cross-version compatibility (including VM migration). Drew will have a more detailed explanation if you need it. thanks -- PMM