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Date: Mon, 16 May 2022 18:12:36 +0200
From: "Rafael J. Wysocki" <rafael@...nel.org>
To: Hans de Goede <hdegoede@...hat.com>
Cc: "Rafael J . Wysocki" <rafael@...nel.org>,
Mika Westerberg <mika.westerberg@...ux.intel.com>,
Krzysztof Wilczyński <kw@...ux.com>,
Bjorn Helgaas <bhelgaas@...gle.com>,
Myron Stowe <myron.stowe@...hat.com>,
Juha-Pekka Heikkila <juhapekka.heikkila@...il.com>,
Thomas Gleixner <tglx@...utronix.de>,
Ingo Molnar <mingo@...hat.com>, Borislav Petkov <bp@...en8.de>,
"H . Peter Anvin" <hpa@...or.com>,
Benoit Grégoire <benoitg@...us.ca>,
Hui Wang <hui.wang@...onical.com>,
ACPI Devel Maling List <linux-acpi@...r.kernel.org>,
Linux PCI <linux-pci@...r.kernel.org>,
"the arch/x86 maintainers" <x86@...nel.org>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v8 1/1] x86/PCI: Ignore E820 reservations for bridge
windows on future systems
On Thu, May 12, 2022 at 10:25 PM Hans de Goede <hdegoede@...hat.com> wrote:
>
> Some BIOS-es contain bugs where they add addresses which are already
> used in some other manner to the PCI host bridge window returned by
> the ACPI _CRS method. To avoid this Linux by default excludes
> E820 reservations when allocating addresses since 2010, see:
> commit 4dc2287c1805 ("x86: avoid E820 regions when allocating address
> space").
>
> Recently (2019) some systems have shown-up with E820 reservations which
> cover the entire _CRS returned PCI bridge memory window, causing all
> attempts to assign memory to PCI BARs which have not been setup by the
> BIOS to fail. For example here are the relevant dmesg bits from a
> Lenovo IdeaPad 3 15IIL 81WE:
>
> [mem 0x000000004bc50000-0x00000000cfffffff] reserved
> pci_bus 0000:00: root bus resource [mem 0x65400000-0xbfffffff window]
>
> The ACPI specifications appear to allow this new behavior:
>
> The relationship between E820 and ACPI _CRS is not really very clear.
> ACPI v6.3, sec 15, table 15-374, says AddressRangeReserved means:
>
> This range of addresses is in use or reserved by the system and is
> not to be included in the allocatable memory pool of the operating
> system's memory manager.
>
> and it may be used when:
>
> The address range is in use by a memory-mapped system device.
>
> Furthermore, sec 15.2 says:
>
> Address ranges defined for baseboard memory-mapped I/O devices, such
> as APICs, are returned as reserved.
>
> A PCI host bridge qualifies as a baseboard memory-mapped I/O device,
> and its apertures are in use and certainly should not be included in
> the general allocatable pool, so the fact that some BIOS-es reports
> the PCI aperture as "reserved" in E820 doesn't seem like a BIOS bug.
>
> So it seems that the excluding of E820 reserved addresses is a mistake.
>
> Ideally Linux would fully stop excluding E820 reserved addresses,
> but then various old systems will regress. Instead keep the old behavior
> for old systems, while ignoring the E820 reservations for any future
> systems.
>
> That is ignore E820 reservations starting with systems with
> a DMI BIOS year >= 2023.
>
> And use DMI quirks for existing systems on which excluding E820
> reservations from the _CRS returned bridge window is an issue.
>
> Also add pci=no_e820 and pci=use_e820 options to allow overriding
> the BIOS year + DMI matching logic.
>
> BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=206459
> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1868899
> BugLink: https://bugzilla.redhat.com/show_bug.cgi?id=1871793
> BugLink: https://bugs.launchpad.net/bugs/1878279
> BugLink: https://bugs.launchpad.net/bugs/1880172
> BugLink: https://bugs.launchpad.net/bugs/1884232
> BugLink: https://bugs.launchpad.net/bugs/1921649
> BugLink: https://bugs.launchpad.net/bugs/1931715
> BugLink: https://bugs.launchpad.net/bugs/1932069
> Cc: Benoit Grégoire <benoitg@...us.ca>
> Cc: Hui Wang <hui.wang@...onical.com>
> Signed-off-by: Hans de Goede <hdegoede@...hat.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@...el.com>
> ---
> Changes in v8:
> - Change the cut-off for no longer excluding E820 reservations from
> the bridge window to BIOS year >= 2023 so that this only applies to
> upcoming systems.
> - Use DMI quirks for existing systems on which excluding E820
> reservations from the _CRS returned bridge window is an issue.
>
> Changes in v7:
> - Re-add the pci=use_e820 and pci=no_e820 kernel cmdline options since it
> turns out that some newer laptops still need pci=use_e820
> - Add DMI quirks for known newer laptops which need pci=use_e820
>
> Changes in v6:
> - Remove the possibility to change the behavior from the commandline
> because of worries that users may use this to paper over other problems
>
> Changes in v5:
> - Drop mention of Windows behavior from the commit msg, replace with a
> reference to the specs
> - Improve documentation in Documentation/admin-guide/kernel-parameters.txt
> - Reword the big comment added, use "PCI host bridge window" in it and drop
> all refences to Windows
>
> Changes in v4:
> - Rewrap the big comment block to fit in 80 columns
> - Add Rafael's Acked-by
> - Add Cc: stable@...r.kernel.org
>
> Changes in v3:
> - Commit msg tweaks (drop dmesg timestamps, typo fix)
> - Use "defined(CONFIG_...)" instead of "defined CONFIG_..."
> - Add Mika's Reviewed-by
>
> Changes in v2:
> - Replace the per model DMI quirk approach with disabling E820 reservations
> checking for all systems with a BIOS year >= 2018
> - Add documentation for the new kernel-parameters to
> Documentation/admin-guide/kernel-parameters.txt
> ---
> .../admin-guide/kernel-parameters.txt | 9 ++
> arch/x86/include/asm/pci_x86.h | 2 +
> arch/x86/pci/acpi.c | 109 +++++++++++++++++-
> arch/x86/pci/common.c | 8 ++
> 4 files changed, 126 insertions(+), 2 deletions(-)
>
> diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
> index 3f1cc5e317ed..2477b639d5c4 100644
> --- a/Documentation/admin-guide/kernel-parameters.txt
> +++ b/Documentation/admin-guide/kernel-parameters.txt
> @@ -4066,6 +4066,15 @@
> please report a bug.
> nocrs [X86] Ignore PCI host bridge windows from ACPI.
> If you need to use this, please report a bug.
> + use_e820 [X86] Use E820 reservations to exclude parts of
> + PCI host bridge windows. This is a workaround
> + for BIOS defects in host bridge _CRS methods.
> + If you need to use this, please report a bug to
> + <linux-pci@...r.kernel.org>.
> + no_e820 [X86] Ignore E820 reservations for PCI host
> + bridge windows. This is the default on modern
> + hardware. If you need to use this, please report
> + a bug to <linux-pci@...r.kernel.org>.
> routeirq Do IRQ routing for all PCI devices.
> This is normally done in pci_enable_device(),
> so this option is a temporary workaround
> diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
> index a0627dfae541..ce3fd3311772 100644
> --- a/arch/x86/include/asm/pci_x86.h
> +++ b/arch/x86/include/asm/pci_x86.h
> @@ -42,6 +42,8 @@ do { \
> #define PCI_ROOT_NO_CRS 0x100000
> #define PCI_NOASSIGN_BARS 0x200000
> #define PCI_BIG_ROOT_WINDOW 0x400000
> +#define PCI_USE_E820 0x800000
> +#define PCI_NO_E820 0x1000000
>
> extern unsigned int pci_probe;
> extern unsigned long pirq_table_addr;
> diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c
> index 562c81a51ea0..125c55b58d7e 100644
> --- a/arch/x86/pci/acpi.c
> +++ b/arch/x86/pci/acpi.c
> @@ -20,6 +20,7 @@ struct pci_root_info {
> #endif
> };
>
> +static bool pci_use_e820 = true;
> static bool pci_use_crs = true;
> static bool pci_ignore_seg;
>
> @@ -42,6 +43,13 @@ static int __init set_ignore_seg(const struct dmi_system_id *id)
> return 0;
> }
>
> +static int __init set_no_e820(const struct dmi_system_id *id)
> +{
> + printk(KERN_INFO "PCI: %s detected: ignoring e820 regions\n", id->ident);
> + pci_use_e820 = false;
> + return 0;
> +}
> +
> static const struct dmi_system_id pci_crs_quirks[] __initconst = {
> /* http://bugzilla.kernel.org/show_bug.cgi?id=14183 */
> {
> @@ -136,6 +144,74 @@ static const struct dmi_system_id pci_crs_quirks[] __initconst = {
> DMI_MATCH(DMI_PRODUCT_NAME, "HP xw9300 Workstation"),
> },
> },
> +
> + /*
> + * Most Lenovo models with "IIL" in their DMI_PRODUCT_VERSION have
> + * an E820 reservation which covers the entire _CRS returned 32 bit
> + * PCI bridge memory window, causing all attempts to assign memory to
> + * 32 bit PCI bars which have not been setup by the BIOS to fail.
> + * Specifically this often causes some of the I2C controllers to not
> + * work breaking touchpad support and/or this may cause issues when
> + * hotplugging thunderbolt connected devices.
> + *
> + * This DMI match entry covers the following DMI_PRODUCT_VERSION-s with
> + * an E820 reservation which covers the entire 32 bit bridge window:
> + * "IdeaPad 3 14IIL05", "IdeaPad 3 15IIL05", "IdeaPad 3 17IIL05",
> + * "IdeaPad 5 14IIL05", "IdeaPad 5 15IIL05",
> + * "IdeaPad Slim 7 14IIL05", "IdeaPad Slim 7 15IIL05",
> + * "Lenovo BS145-15IIL",
> + * "Lenovo IdeaPad S145-15IIL", "Lenovo IdeaPad S340-14IIL",
> + * "Lenovo IdeaPad S340-15IIL", "Lenovo IdeaPad C340-15IIL",
> + * "Lenovo V14-IIL", "Lenovo V15-IIL", "Lenovo V17-IIL",
> + * "Lenovo Yoga S740-14IIL", "Lenovo Yoga C940-14IIL",
> + * "Yoga Slim 7 14IIL05", "Yoga Slim 7 15IIL05"
> + *
> + * On some of these the bridge's _CRS method *sometimes* (under unknown
> + * conditions) has a 64 bit [mem 0x4000000000-0x7fffffffff window].
> + * This avoids some of the issues, but even then there are still issues
> + * with assigning some 32 bit only BARs such as some Thunderbolt devs,
> + * the 00:1f.5 BIOS SPI controller and BAR6 of some nvidia gfx.
> + *
> + * This entry also covers the following DMI_PRODUCT_VERSION-s which do
> + * not need pci_use_e820=false. This quirk is a no-op for these models,
> + * because there is no overlap between E820 regions and _CRS windows:
> + * "IdeaPad Flex 5 14IIL05", "IdeaPad Flex 5 15IIL05",
> + * "Lenovo ThinkBook 14-IIL", "Lenovo ThinkBook 15-IIL",
> + * "Lenovo Yoga S940-14IIL"
> + *
> + * This entry fixes issues reported in the following bugs:
> + * https://bugzilla.kernel.org/show_bug.cgi?id=206459
> + * https://bugzilla.redhat.com/show_bug.cgi?id=1871793
> + * https://bugzilla.redhat.com/show_bug.cgi?id=1868899
> + * https://bugs.launchpad.net/bugs/1878279
> + * https://bugs.launchpad.net/bugs/1880172
> + * https://bugs.launchpad.net/bugs/1921649
> + * https://bugs.launchpad.net/bugs/1931715
> + * https://bugs.launchpad.net/bugs/1932069
> + */
> + {
> + .callback = set_no_e820,
> + .ident = "Lenovo *IIL* product version",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
> + DMI_MATCH(DMI_PRODUCT_VERSION, "IIL"),
> + },
> + },
> +
> + /*
> + * The Acer Spin 5 (SP513-54N) has the same E820 reservation covering
> + * the entire _CRS 32 bit window issue as the Lenovo *IIL* models.
> + * https://bugs.launchpad.net/bugs/1884232
> + */
> + {
> + .callback = set_no_e820,
> + .ident = "Acer Spin 5 (SP513-54N)",
> + .matches = {
> + DMI_MATCH(DMI_SYS_VENDOR, "Acer"),
> + DMI_MATCH(DMI_PRODUCT_NAME, "Spin SP513-54N"),
> + },
> + },
> +
> {}
> };
>
> @@ -146,6 +222,24 @@ void __init pci_acpi_crs_quirks(void)
> if (year >= 0 && year < 2008 && iomem_resource.end <= 0xffffffff)
> pci_use_crs = false;
>
> + /*
> + * Some BIOS-es contain bugs where they add addresses which are already
> + * used in some other manner to the PCI host bridge window returned by
> + * the ACPI _CRS method. To avoid this Linux by default excludes
> + * E820 reservations when allocating addresses since 2010.
> + * In 2019 some systems have shown-up with E820 reservations which cover
> + * the entire _CRS returned PCI host bridge window, causing all attempts
> + * to assign memory to PCI BARs to fail if Linux uses E820 reservations.
> + *
> + * Ideally Linux would fully stop using E820 reservations, but then
> + * various old systems will regress. Instead stop using E820 reservations
> + * for new systems with a DMI BIOS year >= 2023;
> + * and use DMI quirks for existing systems on which excluding E820
> + * reservations is known to cause issues.
> + */
> + if (year >= 2023)
> + pci_use_e820 = false;
> +
> dmi_check_system(pci_crs_quirks);
>
> /*
> @@ -161,6 +255,15 @@ void __init pci_acpi_crs_quirks(void)
> "if necessary, use \"pci=%s\" and report a bug\n",
> pci_use_crs ? "Using" : "Ignoring",
> pci_use_crs ? "nocrs" : "use_crs");
> +
> + /* "pci=use_e820"/"pci=no_e820" on the kernel cmdline takes precedence */
> + if (pci_probe & PCI_NO_E820)
> + pci_use_e820 = false;
> + else if (pci_probe & PCI_USE_E820)
> + pci_use_e820 = true;
> +
> + printk(KERN_INFO "PCI: %s E820 reservations for host bridge windows\n",
> + pci_use_e820 ? "Using" : "Ignoring");
> }
>
> #ifdef CONFIG_PCI_MMCONFIG
> @@ -301,8 +404,10 @@ static int pci_acpi_root_prepare_resources(struct acpi_pci_root_info *ci)
>
> status = acpi_pci_probe_root_resources(ci);
>
> - resource_list_for_each_entry(entry, &ci->resources)
> - remove_e820_regions(&device->dev, entry->res);
> + if (pci_use_e820) {
> + resource_list_for_each_entry(entry, &ci->resources)
> + remove_e820_regions(&device->dev, entry->res);
> + }
>
> if (pci_use_crs) {
> resource_list_for_each_entry_safe(entry, tmp, &ci->resources)
> diff --git a/arch/x86/pci/common.c b/arch/x86/pci/common.c
> index 9e1e6b8d8876..ddb798603201 100644
> --- a/arch/x86/pci/common.c
> +++ b/arch/x86/pci/common.c
> @@ -595,6 +595,14 @@ char *__init pcibios_setup(char *str)
> } else if (!strcmp(str, "nocrs")) {
> pci_probe |= PCI_ROOT_NO_CRS;
> return NULL;
> + } else if (!strcmp(str, "use_e820")) {
> + pci_probe |= PCI_USE_E820;
> + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
> + return NULL;
> + } else if (!strcmp(str, "no_e820")) {
> + pci_probe |= PCI_NO_E820;
> + add_taint(TAINT_FIRMWARE_WORKAROUND, LOCKDEP_STILL_OK);
> + return NULL;
> #ifdef CONFIG_PHYS_ADDR_T_64BIT
> } else if (!strcmp(str, "big_root_window")) {
> pci_probe |= PCI_BIG_ROOT_WINDOW;
> --
> 2.36.0
>
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