From: Rusty Russell <rusty@rustcorp.com.au>
To: "Michael S. Tsirkin" <mst@redhat.com>, linux-kernel@vger.kernel.org
Cc: virtualization@lists.linux-foundation.org
Subject: Re: [PATCH 1/2] virtio_pci_modern: type-safe io accessors
In-Reply-To: <1423977123-10115-1-git-send-email-mst@redhat.com>
References: <1423977123-10115-1-git-send-email-mst@redhat.com>
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Date: Mon, 16 Feb 2015 14:22:55 +1030
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"Michael S. Tsirkin" <mst@redhat.com> writes:
> The spec is very clear on this:
>
> 4.1.3.1 Driver Requirements: PCI Device Layout
>
> The driver MUST access each field using the “natural” access method,
> i.e. 32-bit accesses for 32-bit fields, 16-bit accesses for 16-bit
> fields and 8-bit accesses for 8-bit fields.
>
> Add type-safe wrappers to prevent access with incorrect width.

Applied both (for *next* merge window).

Thanks,
Rusty.

> Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
> ---
>  drivers/virtio/virtio_pci_modern.c | 37 +++++++++++++++++++++++++++++++++++++
>  1 file changed, 37 insertions(+)
>
> diff --git a/drivers/virtio/virtio_pci_modern.c b/drivers/virtio/virtio_pci_modern.c
> index 2aa38e5..4e73ef7 100644
> --- a/drivers/virtio/virtio_pci_modern.c
> +++ b/drivers/virtio/virtio_pci_modern.c
> @@ -20,6 +20,43 @@
>  #define VIRTIO_PCI_NO_LEGACY
>  #include "virtio_pci_common.h"
>  
> +/*
> + * Type-safe wrappers for io accesses.
> + * Use these to enforce at compile time the following spec requirement:
> + *
> + * The driver MUST access each field using the “natural” access
> + * method, i.e. 32-bit accesses for 32-bit fields, 16-bit accesses
> + * for 16-bit fields and 8-bit accesses for 8-bit fields.
> + */
> +static inline u8 vp_ioread8(u8 __iomem *addr)
> +{
> +	return ioread8(addr);
> +}
> +static inline u16 vp_ioread16 (u16 __iomem *addr)
> +{
> +	return ioread16(addr);
> +}
> +
> +static inline u32 vp_ioread32(u32 __iomem *addr)
> +{
> +	return ioread32(addr);
> +}
> +
> +static inline void vp_iowrite8(u8 value, u8 __iomem *addr)
> +{
> +	iowrite8(value, addr);
> +}
> +
> +static inline void vp_iowrite16(u16 value, u16 __iomem *addr)
> +{
> +	iowrite16(value, addr);
> +}
> +
> +static inline void vp_iowrite32(u32 value, u32 __iomem *addr)
> +{
> +	iowrite16(value, addr);
> +}
> +
>  static void __iomem *map_capability(struct pci_dev *dev, int off,
>  				    size_t minlen,
>  				    u32 align,
> -- 
> MST
--
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