Re: [PATCH 3/3] include/hw/ide: Unexport pci_piix3_xen_ide_unplug()

From: "Durrant, Paul" <xadimgnik@gmail.com>
To: Bernhard Beschow <shentey@gmail.com>, qemu-devel@nongnu.org
Cc: qemu-trivial@nongnu.org,
	Stefano Stabellini <sstabellini@kernel.org>,
	Anthony Perard <anthony.perard@citrix.com>,
	Paul Durrant <paul@xen.org>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	Marcel Apfelbaum <marcel.apfelbaum@gmail.com>,
	Paolo Bonzini <pbonzini@redhat.com>,
	Richard Henderson <richard.henderson@linaro.org>,
	Eduardo Habkost <eduardo@habkost.net>,
	John Snow <jsnow@redhat.com>,
	"open list:X86 Xen CPUs" <xen-devel@lists.xenproject.org>,
	"open list:IDE" <qemu-block@nongnu.org>
Subject: Re: [PATCH 3/3] include/hw/ide: Unexport pci_piix3_xen_ide_unplug()
Date: Mon, 9 May 2022 09:02:13 +0100	[thread overview]
Message-ID: <724c6af0-277b-a6d1-b773-89e1b03e0c53@gmail.com> (raw)
In-Reply-To: <20220508103432.14874-4-shentey@gmail.com>

On 08/05/2022 11:34, Bernhard Beschow wrote:
> This function was declared in a generic and public header, implemented
> in a device-specific source file but only used in xen_platform. Given its
> 'aux' parameter, this function is more xen-specific than piix-specific.
> Also, the hardcoded magic constants seem to be generic and related to
> PCIIDEState and IDEBus rather than piix.
> 
> Therefore, move this function to xen_platform, unexport it, and drop the
> "piix3" in the function name as well.
> 
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>

Reviewed-by: Paul Durrant <paul@xen.org>

... with one suggestion...

> ---
>   hw/i386/xen/xen_platform.c | 49 +++++++++++++++++++++++++++++++++++++-
>   hw/ide/piix.c              | 46 -----------------------------------
>   include/hw/ide.h           |  3 ---
>   3 files changed, 48 insertions(+), 50 deletions(-)
> 
> diff --git a/hw/i386/xen/xen_platform.c b/hw/i386/xen/xen_platform.c
> index 72028449ba..124ffeae35 100644
> --- a/hw/i386/xen/xen_platform.c
> +++ b/hw/i386/xen/xen_platform.c
> @@ -26,6 +26,7 @@
>   #include "qemu/osdep.h"
>   #include "qapi/error.h"
>   #include "hw/ide.h"
> +#include "hw/ide/pci.h"
>   #include "hw/pci/pci.h"
>   #include "hw/xen/xen_common.h"
>   #include "migration/vmstate.h"
> @@ -134,6 +135,52 @@ static void pci_unplug_nics(PCIBus *bus)
>       pci_for_each_device(bus, 0, unplug_nic, NULL);
>   }
>   
> +/*
> + * The Xen HVM unplug protocol [1] specifies a mechanism to allow guests to
> + * request unplug of 'aux' disks (which is stated to mean all IDE disks,
> + * except the primary master).
> + *
> + * NOTE: The semantics of what happens if unplug of all disks and 'aux' disks
> + *       is simultaneously requested is not clear. The implementation assumes
> + *       that an 'all' request overrides an 'aux' request.
> + *
> + * [1] https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=docs/misc/hvm-emulated-unplug.pandoc
> + */
> +static int pci_xen_ide_unplug(DeviceState *dev, bool aux)
> +{
> +    PCIIDEState *pci_ide;
> +    int i;
> +    IDEDevice *idedev;
> +    IDEBus *idebus;
> +    BlockBackend *blk;
> +
> +    pci_ide = PCI_IDE(dev);
> +
> +    for (i = aux ? 1 : 0; i < 4; i++) {
> +        idebus = &pci_ide->bus[i / 2];
> +        blk = idebus->ifs[i % 2].blk;
> +
> +        if (blk && idebus->ifs[i % 2].drive_kind != IDE_CD) {
> +            if (!(i % 2)) {
> +                idedev = idebus->master;
> +            } else {
> +                idedev = idebus->slave;
> +            }
> +
> +            blk_drain(blk);
> +            blk_flush(blk);
> +
> +            blk_detach_dev(blk, DEVICE(idedev));
> +            idebus->ifs[i % 2].blk = NULL;
> +            idedev->conf.blk = NULL;
> +            monitor_remove_blk(blk);
> +            blk_unref(blk);
> +        }
> +    }
> +    qdev_reset_all(dev);
> +    return 0;

The return value is ignored so you may as well make this a static void 
function.

   Paul

> +}
> +
>   static void unplug_disks(PCIBus *b, PCIDevice *d, void *opaque)
>   {
>       uint32_t flags = *(uint32_t *)opaque;
> @@ -147,7 +194,7 @@ static void unplug_disks(PCIBus *b, PCIDevice *d, void *opaque)
>   
>       switch (pci_get_word(d->config + PCI_CLASS_DEVICE)) {
>       case PCI_CLASS_STORAGE_IDE:
> -        pci_piix3_xen_ide_unplug(DEVICE(d), aux);
> +        pci_xen_ide_unplug(DEVICE(d), aux);
>           break;
>   
>       case PCI_CLASS_STORAGE_SCSI:
> diff --git a/hw/ide/piix.c b/hw/ide/piix.c
> index bc1b37512a..9a9b28078e 100644
> --- a/hw/ide/piix.c
> +++ b/hw/ide/piix.c
> @@ -173,52 +173,6 @@ static void pci_piix_ide_realize(PCIDevice *dev, Error **errp)
>       }
>   }
>   
> -/*
> - * The Xen HVM unplug protocol [1] specifies a mechanism to allow guests to
> - * request unplug of 'aux' disks (which is stated to mean all IDE disks,
> - * except the primary master).
> - *
> - * NOTE: The semantics of what happens if unplug of all disks and 'aux' disks
> - *       is simultaneously requested is not clear. The implementation assumes
> - *       that an 'all' request overrides an 'aux' request.
> - *
> - * [1] https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=docs/misc/hvm-emulated-unplug.pandoc
> - */
> -int pci_piix3_xen_ide_unplug(DeviceState *dev, bool aux)
> -{
> -    PCIIDEState *pci_ide;
> -    int i;
> -    IDEDevice *idedev;
> -    IDEBus *idebus;
> -    BlockBackend *blk;
> -
> -    pci_ide = PCI_IDE(dev);
> -
> -    for (i = aux ? 1 : 0; i < 4; i++) {
> -        idebus = &pci_ide->bus[i / 2];
> -        blk = idebus->ifs[i % 2].blk;
> -
> -        if (blk && idebus->ifs[i % 2].drive_kind != IDE_CD) {
> -            if (!(i % 2)) {
> -                idedev = idebus->master;
> -            } else {
> -                idedev = idebus->slave;
> -            }
> -
> -            blk_drain(blk);
> -            blk_flush(blk);
> -
> -            blk_detach_dev(blk, DEVICE(idedev));
> -            idebus->ifs[i % 2].blk = NULL;
> -            idedev->conf.blk = NULL;
> -            monitor_remove_blk(blk);
> -            blk_unref(blk);
> -        }
> -    }
> -    qdev_reset_all(dev);
> -    return 0;
> -}
> -
>   static void pci_piix_ide_exitfn(PCIDevice *dev)
>   {
>       PCIIDEState *d = PCI_IDE(dev);
> diff --git a/include/hw/ide.h b/include/hw/ide.h
> index c5ce5da4f4..60f1f4f714 100644
> --- a/include/hw/ide.h
> +++ b/include/hw/ide.h
> @@ -8,9 +8,6 @@
>   ISADevice *isa_ide_init(ISABus *bus, int iobase, int iobase2, int isairq,
>                           DriveInfo *hd0, DriveInfo *hd1);
>   
> -/* ide-pci.c */
> -int pci_piix3_xen_ide_unplug(DeviceState *dev, bool aux);
> -
>   /* ide-mmio.c */
>   void mmio_ide_init_drives(DeviceState *dev, DriveInfo *hd0, DriveInfo *hd1);
>   