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Date:   Tue, 26 Oct 2021 15:08:20 +0100
From:   Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
To:     "Rafael J. Wysocki" <rafael@kernel.org>
Cc:     Xuesong Chen <xuesong.chen@linux.alibaba.com>,
        Bjorn Helgaas <bhelgaas@google.com>,
        Catalin Marinas <catalin.marinas@arm.com>,
        James Morse <james.morse@arm.com>,
        Will Deacon <will@kernel.org>, Tony Luck <tony.luck@intel.com>,
        Borislav Petkov <bp@alien8.de>, Ingo Molnar <mingo@kernel.org>,
        Linux PCI <linux-pci@vger.kernel.org>,
        ACPI Devel Maling List <linux-acpi@vger.kernel.org>,
        Linux ARM <linux-arm-kernel@lists.infradead.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v3 1/2] PCI: MCFG: Consolidate the separate PCI MCFG
 table entry list
Message-ID: <20211026140820.GA19689@lpieralisi>
References: <YW5OdIyFkTYo0h3W@Dennis-MBP.local>
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On Tue, Oct 26, 2021 at 03:14:37PM +0200, Rafael J. Wysocki wrote:
> On Tue, Oct 19, 2021 at 6:50 AM Xuesong Chen
> <xuesong.chen@linux.alibaba.com> wrote:
> >
> > The PCI MCFG entry list is discrete on x86 and other arches like ARM64
> > in current implementation, this list variable can be consolidated for
> > unnecessary duplication and other purposes, for example, we can remove
> > some of the arch-specific codes in the APEI/EINJ module and re-implement
> > it in a more common arch-agnostic way.
> >
> > To reduce the redundancy, it:
> >   - Moves the "struct pci_mmcfg_region" definition from
> >     arch/x86/include/asm/pci_x86.h to include/linux/pci.h, where it
> >     can be shared across arches.
> >
> >   - Moves pci_mmcfg_list (a list of pci_mmcfg_region structs) from
> >     arch/x86/pci/mmconfig-shared.c to drivers/pci/pci.c, where it can
> >     be shared across arches.
> >
> >   - On x86 (which does not enable CONFIG_ACPI_MCFG), pci_mmcfg_list is
> >     built in arch/x86/pci/mmconfig-shared.c as before.
> >
> >   - Removes the "struct mcfg_entry" from drivers/acpi/pci_mcfg.c.
> >
> >   - Replaces pci_mcfg_list (previously a list of mcfg_entry structs)
> >     in drivers/acpi/pci_mcfg.c with the newly-shared pci_mmcfg_list (a
> >     list of pci_mmcfg_region structs).
> >
> >   - On ARM64 (which does enable CONFIG_ACPI_MCFG), pci_mmcfg_list is
> >     built in drivers/acpi/pci_mcfg.c.
> >
> > Signed-off-by: Xuesong Chen <xuesong.chen@linux.alibaba.com>
> > Reviewed-by: Bjorn Helgaas <bhelgaas@google.com>
> > Reviewed-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
> 
> I'm guessing that I'm expected to pick up this one?

I did not provide a Reviewed-by: tag for this patch (and I don't
think Bjorn provided his either).

That's valid also for patch 2:

https://lore.kernel.org/linux-pci/20211019150405.GA2338201@bhelgaas

> > Cc: Catalin Marinas <catalin.marinas@arm.com>
> > Cc: James Morse <james.morse@arm.com>
> > Cc: Will Deacon <will@kernel.org>
> > Cc: Rafael. J. Wysocki <rafael@kernel.org>
> > Cc: Tony Luck <tony.luck@intel.com>
> > Cc: Tomasz Nowicki <tn@semihalf.com>
> > ---
> >  arch/x86/include/asm/pci_x86.h | 17 +----------------
> >  arch/x86/pci/mmconfig-shared.c |  2 --
> >  drivers/acpi/pci_mcfg.c        | 34 +++++++++++++---------------------
> >  drivers/pci/pci.c              |  2 ++
> >  include/linux/pci.h            | 17 +++++++++++++++++
> >  5 files changed, 33 insertions(+), 39 deletions(-)
> >
> > diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
> > index 490411d..1f4257c 100644
> > --- a/arch/x86/include/asm/pci_x86.h
> > +++ b/arch/x86/include/asm/pci_x86.h
> > @@ -146,20 +146,7 @@ static inline int  __init pci_acpi_init(void)
> >  extern void pcibios_fixup_irqs(void);
> >
> >  /* pci-mmconfig.c */
> > -
> > -/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
> > -#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
> > -
> > -struct pci_mmcfg_region {
> > -       struct list_head list;
> > -       struct resource res;
> > -       u64 address;
> > -       char __iomem *virt;
> > -       u16 segment;
> > -       u8 start_bus;
> > -       u8 end_bus;
> > -       char name[PCI_MMCFG_RESOURCE_NAME_LEN];
> > -};
> > +struct pci_mmcfg_region;
> >
> >  extern int __init pci_mmcfg_arch_init(void);
> >  extern void __init pci_mmcfg_arch_free(void);
> > @@ -174,8 +161,6 @@ extern struct pci_mmcfg_region *__init pci_mmconfig_add(int segment, int start,
> >
> >  extern struct list_head pci_mmcfg_list;
> >
> > -#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
> > -
> >  /*
> >   * On AMD Fam10h CPUs, all PCI MMIO configuration space accesses must use
> >   * %eax.  No other source or target registers may be used.  The following
> > diff --git a/arch/x86/pci/mmconfig-shared.c b/arch/x86/pci/mmconfig-shared.c
> > index 758cbfe..0b961fe6 100644
> > --- a/arch/x86/pci/mmconfig-shared.c
> > +++ b/arch/x86/pci/mmconfig-shared.c
> > @@ -31,8 +31,6 @@
> >  static DEFINE_MUTEX(pci_mmcfg_lock);
> >  #define pci_mmcfg_lock_held() lock_is_held(&(pci_mmcfg_lock).dep_map)
> >
> > -LIST_HEAD(pci_mmcfg_list);
> > -
> >  static void __init pci_mmconfig_remove(struct pci_mmcfg_region *cfg)
> >  {
> >         if (cfg->res.parent)
> > diff --git a/drivers/acpi/pci_mcfg.c b/drivers/acpi/pci_mcfg.c
> > index 53cab97..d9506b0 100644
> > --- a/drivers/acpi/pci_mcfg.c
> > +++ b/drivers/acpi/pci_mcfg.c
> > @@ -13,14 +13,7 @@
> >  #include <linux/pci-acpi.h>
> >  #include <linux/pci-ecam.h>
> >
> > -/* Structure to hold entries from the MCFG table */
> > -struct mcfg_entry {
> > -       struct list_head        list;
> > -       phys_addr_t             addr;
> > -       u16                     segment;
> > -       u8                      bus_start;
> > -       u8                      bus_end;
> > -};
> > +extern struct list_head pci_mmcfg_list;
> >
> >  #ifdef CONFIG_PCI_QUIRKS
> >  struct mcfg_fixup {
> > @@ -214,16 +207,13 @@ static void pci_mcfg_apply_quirks(struct acpi_pci_root *root,
> >  #endif
> >  }
> >
> > -/* List to save MCFG entries */
> > -static LIST_HEAD(pci_mcfg_list);
> > -
> >  int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
> >                     const struct pci_ecam_ops **ecam_ops)
> >  {
> >         const struct pci_ecam_ops *ops = &pci_generic_ecam_ops;
> >         struct resource *bus_res = &root->secondary;
> >         u16 seg = root->segment;
> > -       struct mcfg_entry *e;
> > +       struct pci_mmcfg_region *e;
> >         struct resource res;
> >
> >         /* Use address from _CBA if present, otherwise lookup MCFG */
> > @@ -233,10 +223,10 @@ int pci_mcfg_lookup(struct acpi_pci_root *root, struct resource *cfgres,
> >         /*
> >          * We expect the range in bus_res in the coverage of MCFG bus range.
> >          */
> > -       list_for_each_entry(e, &pci_mcfg_list, list) {
> > -               if (e->segment == seg && e->bus_start <= bus_res->start &&
> > -                   e->bus_end >= bus_res->end) {
> > -                       root->mcfg_addr = e->addr;
> > +       list_for_each_entry(e, &pci_mmcfg_list, list) {
> > +               if (e->segment == seg && e->start_bus <= bus_res->start &&
> > +                   e->end_bus >= bus_res->end) {
> > +                       root->mcfg_addr = e->address;
> >                 }
> >
> >         }
> > @@ -268,7 +258,7 @@ static __init int pci_mcfg_parse(struct acpi_table_header *header)
> >  {
> >         struct acpi_table_mcfg *mcfg;
> >         struct acpi_mcfg_allocation *mptr;
> > -       struct mcfg_entry *e, *arr;
> > +       struct pci_mmcfg_region *e, *arr;
> >         int i, n;
> >
> >         if (header->length < sizeof(struct acpi_table_mcfg))
> > @@ -285,10 +275,12 @@ static __init int pci_mcfg_parse(struct acpi_table_header *header)
> >
> >         for (i = 0, e = arr; i < n; i++, mptr++, e++) {
> >                 e->segment = mptr->pci_segment;
> > -               e->addr =  mptr->address;
> > -               e->bus_start = mptr->start_bus_number;
> > -               e->bus_end = mptr->end_bus_number;
> > -               list_add(&e->list, &pci_mcfg_list);
> > +               e->address =  mptr->address;
> > +               e->start_bus = mptr->start_bus_number;
> > +               e->end_bus = mptr->end_bus_number;
> > +               e->res.start = e->address + PCI_MMCFG_BUS_OFFSET(e->start_bus);
> > +               e->res.end = e->address + PCI_MMCFG_BUS_OFFSET(e->end_bus + 1) - 1;
> > +               list_add(&e->list, &pci_mmcfg_list);
> >         }
> >
> >  #ifdef CONFIG_PCI_QUIRKS
> > diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
> > index ce2ab62..899004e 100644
> > --- a/drivers/pci/pci.c
> > +++ b/drivers/pci/pci.c
> > @@ -47,6 +47,8 @@
> >  int pci_pci_problems;
> >  EXPORT_SYMBOL(pci_pci_problems);
> >
> > +LIST_HEAD(pci_mmcfg_list);
> > +
> >  unsigned int pci_pm_d3hot_delay;
> >
> >  static void pci_pme_list_scan(struct work_struct *work);
> > diff --git a/include/linux/pci.h b/include/linux/pci.h
> > index cd8aa6f..71e4c06 100644
> > --- a/include/linux/pci.h
> > +++ b/include/linux/pci.h
> > @@ -55,6 +55,23 @@
> >  #define PCI_RESET_PROBE                true
> >  #define PCI_RESET_DO_RESET     false
> >
> > +#define PCI_MMCFG_BUS_OFFSET(bus)      ((bus) << 20)
> > +
> > +/* "PCI MMCONFIG %04x [bus %02x-%02x]" */
> > +#define PCI_MMCFG_RESOURCE_NAME_LEN (22 + 4 + 2 + 2)
> > +
> > +/* pci mcfg region */
> > +struct pci_mmcfg_region {
> > +       struct list_head list;
> > +       struct resource res;
> > +       u64 address;
> > +       char __iomem *virt;
> > +       u16 segment;
> > +       u8 start_bus;
> > +       u8 end_bus;
> > +       char name[PCI_MMCFG_RESOURCE_NAME_LEN];
> > +};
> > +
> >  /*
> >   * The PCI interface treats multi-function devices as independent
> >   * devices.  The slot/function address of each device is encoded
> > --
> > 1.8.3.1
> >