Re: [Qemu-devel] [PATCH 3/5] pci: designware: Update MSI mapping unconditionally

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

On Mon, Apr 15, 2019 at 06:39:00PM -0700, Andrey Smirnov wrote:
> Expression to calculate update_msi_mapping in code handling writes to
> DESIGNWARE_PCIE_MSI_INTR0_ENABLE is missing an ! operator and should
> be:
> 
>     !!root->msi.intr[0].enable ^ !!val;
> 
> so that MSI mapping is updated when enabled transitions from either
> "none" -> "any" or "any" -> "none". Since that register shouldn't be
> written to very often, change the code to update MSI mapping
> unconditionally instead of trying to fix the update_msi_mapping logic.
> 
> Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com>
> Cc: Peter Maydell <peter.maydell@linaro.org>
> Cc: Michael S. Tsirkin <mst@redhat.com>
> Cc: qemu-devel@nongnu.org
> Cc: qemu-arm@nongnu.org

Acked-by: Michael S. Tsirkin <mst@redhat.com>

> ---
>  hw/pci-host/designware.c | 10 ++--------
>  1 file changed, 2 insertions(+), 8 deletions(-)
> 
> diff --git a/hw/pci-host/designware.c b/hw/pci-host/designware.c
> index 29ea313798..6affe823c0 100644
> --- a/hw/pci-host/designware.c
> +++ b/hw/pci-host/designware.c
> @@ -296,16 +296,10 @@ static void designware_pcie_root_config_write(PCIDevice *d, uint32_t address,
>          root->msi.base |= (uint64_t)val << 32;
>          break;
>  
> -    case DESIGNWARE_PCIE_MSI_INTR0_ENABLE: {
> -        const bool update_msi_mapping = !root->msi.intr[0].enable ^ !!val;
> -
> +    case DESIGNWARE_PCIE_MSI_INTR0_ENABLE:
>          root->msi.intr[0].enable = val;
> -
> -        if (update_msi_mapping) {
> -            designware_pcie_root_update_msi_mapping(root);
> -        }
> +        designware_pcie_root_update_msi_mapping(root);
>          break;
> -    }
>  
>      case DESIGNWARE_PCIE_MSI_INTR0_MASK:
>          root->msi.intr[0].mask = val;
> -- 
> 2.20.1