On Fri, Oct 08, 2021 at 04:31:43PM -0500, Bjorn Helgaas wrote: > [+cc Jayachandran, Tomasz; not sure if they're still around, but just > in case they have a comment on any reasons for keeping the > pci_mcfg_list list separate.] > > On Fri, Oct 08, 2021 at 04:40:12PM +0800, Xuesong Chen wrote: > > The PCI MCFG entry list is discrete on x86 and other architectures 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. > > This commit log could be more explicit about what's going on here. > > From deciphering the patch, I think it takes advantage of the fact > that struct pci_mmcfg_region and struct mcfg_entry contain basically > the same information, but pci_mmcfg_region contains a little extra > information (a struct resource, a virtual address, and a name). > > 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. This is a bit ugly, especially the resulting ifdef CONFIG_PCI in patch 2: https://lore.kernel.org/linux-acpi/YWAEG7fyFC+lhwd+@Dennis-MBP.local I'd rather make apei_filter_mcfg_addr() conditional, on what, that's the question. #ifdef CONFIG_FOO static int apei_filter_mcfg_addr() { ... } #else static inline int apei_filter_mcfg_addr() { return 0; } #endif > - 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. > > Does that sound about right? Yes it does. Another option would consist in doing all the MCFG parsing (anew) in APEI code to build a temporary list that is discarded as soon as the resource filtering took place - maybe it is something worth thinking about (but do we really need more MCFG parsing code ?). Lorenzo > > Signed-off-by: Xuesong Chen <xuesong.chen@xxxxxxxxxxxxxxxxx> > > --- > > 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 > >
