Re: [PATCH v4 4/4] via-ide: Also emulate non 100% native mode

[Mark Cave-Ayland]

On 10/03/2020 19:06, BALATON Zoltan wrote:

> Some machines operate in "non 100% native mode" where interrupts are
> fixed at legacy IDE interrupts and some guests expect this behaviour
> without checking based on knowledge about hardware. Even Linux has
> arch specific workarounds for this that are activated on such boards
> so this needs to be emulated as well.
> 
> Signed-off-by: BALATON Zoltan <address@hidden>
> ---
> 
> Notes:
>     v2: Don't use PCI_INTERRUPT_LINE in via_ide_set_irq()
>     v3: Patch pci.c instead of local workaround for PCI reset clearing
>         PCI_INTERRUPT_PIN config reg
> 
>  hw/ide/via.c | 30 ++++++++++++++++++++++++------
>  1 file changed, 24 insertions(+), 6 deletions(-)
> 
> diff --git a/hw/ide/via.c b/hw/ide/via.c
> index df0b352b58..1eada23097 100644
> --- a/hw/ide/via.c
> +++ b/hw/ide/via.c
> @@ -1,9 +1,10 @@
>  /*
> - * QEMU IDE Emulation: PCI VIA82C686B support.
> + * QEMU VIA southbridge IDE emulation (VT82C686B, VT8231)
>   *
>   * Copyright (c) 2003 Fabrice Bellard
>   * Copyright (c) 2006 Openedhand Ltd.
>   * Copyright (c) 2010 Huacai Chen <address@hidden>
> + * Copyright (c) 2019-2020 BALATON Zoltan
>   *
>   * Permission is hereby granted, free of charge, to any person obtaining a 
> copy
>   * of this software and associated documentation files (the "Software"), to 
> deal
> @@ -25,6 +26,7 @@
>   */
>  
>  #include "qemu/osdep.h"
> +#include "hw/qdev-properties.h"
>  #include "hw/pci/pci.h"
>  #include "migration/vmstate.h"
>  #include "qemu/module.h"
> @@ -111,11 +113,18 @@ static void via_ide_set_irq(void *opaque, int n, int 
> level)
>      } else {
>          d->config[0x70 + n * 8] &= ~0x80;
>      }
> -
>      level = (d->config[0x70] & 0x80) || (d->config[0x78] & 0x80);
> -    n = pci_get_byte(d->config + PCI_INTERRUPT_LINE);
> -    if (n) {
> -        qemu_set_irq(isa_get_irq(NULL, n), level);
> +
> +    /*
> +     * Some machines operate in "non 100% native mode" where 
> PCI_INTERRUPT_LINE
> +     * is not used but IDE always uses ISA IRQ 14 and 15 even in native mode.
> +     * Some guest drivers expect this, often without checking.
> +     */
> +    if (!(pci_get_byte(d->config + PCI_CLASS_PROG) & (n ? 4 : 1)) ||
> +        PCI_IDE(d)->flags & BIT(PCI_IDE_LEGACY_IRQ)) {
> +        qemu_set_irq(isa_get_irq(NULL, (n ? 15 : 14)), level);
> +    } else {
> +        qemu_set_irq(isa_get_irq(NULL, 14), level);
>      }
>  }
>  
> @@ -169,7 +178,9 @@ static void via_ide_realize(PCIDevice *dev, Error **errp)
>  
>      pci_config_set_prog_interface(pci_conf, 0x8f); /* native PCI ATA mode */
>      pci_set_long(pci_conf + PCI_CAPABILITY_LIST, 0x000000c0);
> -    dev->wmask[PCI_INTERRUPT_LINE] = 0xf;
> +    /* Bits 0 and 4 of CLASS_PROG select native mode and are writable */
> +    dev->wmask[PCI_CLASS_PROG] = 5;
> +    dev->wmask[PCI_INTERRUPT_LINE] = 0;
>  
>      memory_region_init_io(&d->data_bar[0], OBJECT(d), &pci_ide_data_le_ops,
>                            &d->bus[0], "via-ide0-data", 8);
> @@ -213,6 +224,12 @@ static void via_ide_exitfn(PCIDevice *dev)
>      }
>  }
>  
> +static Property via_ide_properties[] = {
> +    DEFINE_PROP_BIT("legacy-irq", PCIIDEState, flags, PCI_IDE_LEGACY_IRQ,
> +                    false),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
>  static void via_ide_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
> @@ -225,6 +242,7 @@ static void via_ide_class_init(ObjectClass *klass, void 
> *data)
>      k->device_id = PCI_DEVICE_ID_VIA_IDE;
>      k->revision = 0x06;
>      k->class_id = PCI_CLASS_STORAGE_IDE;
> +    device_class_set_props(dc, via_ide_properties);
>      set_bit(DEVICE_CATEGORY_STORAGE, dc->categories);
>  }

I don't think this (and adding the feature bit) are the right solution here. 
I'll do
my best to look at the test cases you've sent off-list over the next couple of 
days
and report back.


ATB,

Mark.