[Qemu-devel] Re: [PATCH v2 1/2] pci: introduce pci_region to manage pci io/memory/prefmemory regions.

["Michael S. Tsirkin" <mst@redhat.com>]

On Thu, Oct 28, 2010 at 02:04:05PM +0900, Isaku Yamahata wrote:
> This patch adds helper functions to manage pci area.
> 
> Signed-off-by: Isaku Yamahata <yamahata@valinux.co.jp>
> 
> ---
> Changes v1 -> v2
> - add comments
> ---
>  Makefile         |    3 +-
>  src/pci_region.c |   77 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
>  src/util.h       |   28 +++++++++++++++++++
>  3 files changed, 107 insertions(+), 1 deletions(-)
>  create mode 100644 src/pci_region.c
> 
> diff --git a/Makefile b/Makefile
> index 9d412f1..1663a5d 100644
> --- a/Makefile
> +++ b/Makefile
> @@ -19,7 +19,8 @@ SRCBOTH=misc.c pmm.c stacks.c output.c util.c block.c floppy.c ata.c mouse.c \
>  SRC16=$(SRCBOTH) system.c disk.c font.c
>  SRC32FLAT=$(SRCBOTH) post.c shadow.c memmap.c coreboot.c boot.c \
>        acpi.c smm.c mptable.c smbios.c pciinit.c optionroms.c mtrr.c \
> -      lzmadecode.c bootsplash.c jpeg.c usb-hub.c paravirt.c dev-i440fx.c
> +      lzmadecode.c bootsplash.c jpeg.c usb-hub.c paravirt.c dev-i440fx.c \
> +      pci_region.c
>  SRC32SEG=util.c output.c pci.c pcibios.c apm.c stacks.c
>  
>  cc-option = $(shell if test -z "`$(1) $(2) -S -o /dev/null -xc \
> diff --git a/src/pci_region.c b/src/pci_region.c
> new file mode 100644
> index 0000000..c8656cb
> --- /dev/null
> +++ b/src/pci_region.c
> @@ -0,0 +1,77 @@
> +// helper functions to manage pci io/memory/prefetch memory region
> +//
> +// Copyright (C) 2009 Isaku Yamahata <yamahata at valinux co jp>
> +//
> +// This file may be distributed under the terms of the GNU LGPLv3 license.
> +//
> +//
> +
> +#include "util.h"
> +
> +#define PCI_REGION_DISABLED     (-1)
> +
> +void pci_region_init(struct pci_region *r, u32 start, u32 end)
> +{
> +    r->start = start;
> +    r->end = end;
> +
> +    r->cur_end = start;
> +}
> +
> +// PCI_REGION_DISABLED represents that the region is in special state.
> +// its value is chosen such that cur_end can't be PCI_REGION_DISABLED normally.
> +u32 pci_region_disable(struct pci_region *r)
> +{
> +    return r->cur_end = PCI_REGION_DISABLED;
> +}
> +
> +static int pci_region_disabled(const struct pci_region *r)
> +{
> +    return r->cur_end == PCI_REGION_DISABLED;
> +}
> +
> +static u32 pci_region_alloc_align(struct pci_region *r, u32 size, u32 align)
> +{
> +    if (pci_region_disabled(r)) {
> +        return 0;
> +    }
> +
> +    u32 s = ALIGN(r->cur_end, align);
> +    if (s > r->end || s < r->cur_end) {
> +        return 0;
> +    }
> +    u32 e = s + size;
> +    if (e > r->end || e < s) {
> +        return 0;
> +    }
> +    r->cur_end = e;
> +    return s;
> +}
> +
> +u32 pci_region_alloc(struct pci_region *r, u32 size)
> +{
> +    return pci_region_alloc_align(r, size, size);
> +}
> +
> +u32 pci_region_align(struct pci_region *r, u32 align)
> +{
> +    return pci_region_alloc_align(r, 0, align);
> +}
> +
> +void pci_region_revert(struct pci_region *r, u32 addr)
> +{
> +    r->cur_end = addr;
> +}
> +
> +u32 pci_region_addr(const struct pci_region *r)
> +{
> +    if (pci_region_disabled(r)){
> +        return r->end;
> +    }
> +    return r->cur_end;
> +}
> +
> +u32 pci_region_size(const struct pci_region *r)
> +{
> +    return r->end - r->start;
> +}
> diff --git a/src/util.h b/src/util.h
> index 5cc9f17..17eedd0 100644
> --- a/src/util.h
> +++ b/src/util.h
> @@ -344,6 +344,34 @@ void qemu_prep_reset(void);
>  void smm_save_and_copy(void);
>  void smm_relocate_and_restore(void);
>  
> +// pci_region.c
> +// region allocator. pci region allocates the requested region
> +// sequentially with overflow check.
> +struct pci_region {
> +    // The region is [start, region).

[start end)?

> +    u32 start;
> +    u32 end;
> +
> +    // The next allocation is start from this.
> +    // i.e. [start, cur_end) is allocated.
> +    // Right after initialization cur_end == start.
> +    u32 cur_end;

What is the value for a region at 0xfffff000 and size 0x1000?

Maybe first, last is better to detect this?

> +};
> +// initialize the pci_region of [start, end)
> +void pci_region_init(struct pci_region *r, u32 start, u32 end);
> +// allocate the region of size
> +u32 pci_region_alloc(struct pci_region *r, u32 size);
> +// make the next allocation aligned to align
> +u32 pci_region_align(struct pci_region *r, u32 align);
> +// revert the allocation to addr.
> +void pci_region_revert(struct pci_region *r, u32 addr);
> +// make the allocation fail.
> +u32 pci_region_disable(struct pci_region *r);
> +// returns the current allocation point.
> +u32 pci_region_addr(const struct pci_region *r);
> +// returns the region size.
> +u32 pci_region_size(const struct pci_region *r);
> +
>  // pciinit.c
>  extern const u8 pci_irqs[4];
>  void pci_bios_allocate_regions(u16 bdf, void *arg);
> -- 
> 1.7.1.1