Re: [PATCH] hw/pci: Display correct size for unmapped BARs in HMP 'info pci'

[BALATON Zoltan <balaton@eik.bme.hu>]

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On Tue, 3 Jan 2023, Philippe Mathieu-Daudé wrote:
> When a BAR is not mapped, the displayed size is shifted by 1 byte:
>
>  (qemu) info pci
>    ...
>    Bus  0, device  11, function 0:
>      Ethernet controller: PCI device 1022:2000
>        PCI subsystem 0000:0000
>        IRQ 10, pin A
>        BAR0: I/O at 0xffffffffffffffff [0x001e].
>        BAR1: 32 bit memory at 0xffffffffffffffff [0x0000001e].   <===
>        BAR6: 32 bit memory at 0xffffffffffffffff [0x0003fffe].   <===
>        id ""
>    Bus  0, device  18, function 0:
>      VGA controller: PCI device 1013:00b8
>        PCI subsystem 1af4:1100
>        BAR0: 32 bit prefetchable memory at 0x10000000 [0x11ffffff].
>        BAR1: 32 bit memory at 0x12050000 [0x12050fff].
>        BAR6: 32 bit memory at 0xffffffffffffffff [0x0000fffe].   <===
>        id ""
>
> Only substract this byte when the BAR is mapped to display
> the correct size:
>
>  (qemu) info pci
>    ...
>    Bus  0, device  11, function 0:
>      Ethernet controller: PCI device 1022:2000
>        PCI subsystem 0000:0000
>        IRQ 10, pin A
>        BAR0: I/O at 0xffffffffffffffff [0x001f].
>        BAR1: 32 bit memory at 0xffffffffffffffff [0x0000001f].   <===
>        BAR6: 32 bit memory at 0xffffffffffffffff [0x0003ffff].   <===
>        id ""
>    Bus  0, device  18, function 0:
>      VGA controller: PCI device 1013:00b8
>        PCI subsystem 1af4:1100
>        BAR0: 32 bit prefetchable memory at 0x10000000 [0x11ffffff].
>        BAR1: 32 bit memory at 0x12050000 [0x12050fff].
>        BAR6: 32 bit memory at 0xffffffffffffffff [0x0000ffff].   <===
>        id ""
>
> Fixes: 0ac32c8375 ("PCI interrupt support - 'info pci' monitor command")
> Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
> ---
> hw/pci/pci-hmp-cmds.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/hw/pci/pci-hmp-cmds.c b/hw/pci/pci-hmp-cmds.c
> index fb7591d6ab..8cfa5f9cd1 100644
> --- a/hw/pci/pci-hmp-cmds.c
> +++ b/hw/pci/pci-hmp-cmds.c
> @@ -75,22 +75,24 @@ static void hmp_info_pci_device(Monitor *mon, const PciDeviceInfo *dev)
>
>     for (region = dev->regions; region; region = region->next) {
>         uint64_t addr, size;
> +        bool mapped;
>
>         addr = region->value->address;
>         size = region->value->size;

As size is not used for anything else, you could adjust the value here 
once either as

size = region->value->size - (addr != -1 ? 1 : 0);

or in an if then you don't need the bool and tweak the value when 
printing. This looks simpler to me.

Regards,
BALATON Zoltan

> +        mapped = addr != -1;
>
>         monitor_printf(mon, "      BAR%" PRId64 ": ", region->value->bar);
>
>         if (!strcmp(region->value->type, "io")) {
>             monitor_printf(mon, "I/O at 0x%04" PRIx64
>                                 " [0x%04" PRIx64 "].\n",
> -                           addr, addr + size - 1);
> +                           addr, addr + size + (mapped ? -1 : 0));
>         } else {
>             monitor_printf(mon, "%d bit%s memory at 0x%08" PRIx64
>                                " [0x%08" PRIx64 "].\n",
>                            region->value->mem_type_64 ? 64 : 32,
>                            region->value->prefetch ? " prefetchable" : "",
> -                           addr, addr + size - 1);
> +                           addr, addr + size + (mapped ? -1 : 0));
>         }
>     }
>
>