On Thu, Sep 30, 2021 at 10:52:20AM +0300, Oleksandr Andrushchenko wrote:
> From: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
>
> Add basic emulation support for guests. At the moment only emulate
> PCI_COMMAND_INTX_DISABLE bit, the rest is not emulated yet and left
> as TODO.
>
> Signed-off-by: Oleksandr Andrushchenko <oleksandr_andrushche...@epam.com>
> Reviewed-by: Michal Orzel <michal.or...@arm.com>
> ---
> New in v2
> ---
> xen/drivers/vpci/header.c | 35 ++++++++++++++++++++++++++++++++---
> 1 file changed, 32 insertions(+), 3 deletions(-)
>
> diff --git a/xen/drivers/vpci/header.c b/xen/drivers/vpci/header.c
> index f23c956cde6c..754aeb5a584f 100644
> --- a/xen/drivers/vpci/header.c
> +++ b/xen/drivers/vpci/header.c
> @@ -451,6 +451,32 @@ static void cmd_write(const struct pci_dev *pdev,
> unsigned int reg,
> pci_conf_write16(pdev->sbdf, reg, cmd);
> }
>
> +static void guest_cmd_write(const struct pci_dev *pdev, unsigned int reg,
> + uint32_t cmd, void *data)
> +{
> + /* TODO: Add proper emulation for all bits of the command register. */
> +
> + if ( (cmd & PCI_COMMAND_INTX_DISABLE) == 0 )
> + {
> + /*
> + * Guest wants to enable INTx. It can't be enabled if:
> + * - host has INTx disabled
> + * - MSI/MSI-X enabled
> + */
> + if ( pdev->vpci->msi->enabled )
> + cmd |= PCI_COMMAND_INTX_DISABLE;
> + else
> + {
> + uint16_t current_cmd = pci_conf_read16(pdev->sbdf, reg);
> +
> + if ( current_cmd & PCI_COMMAND_INTX_DISABLE )
> + cmd |= PCI_COMMAND_INTX_DISABLE;
> + }
This last part should be Arm specific. On other architectures we
likely want the guest to modify INTx disable in order to select the
interrupt delivery mode for the device.
I really wonder if we should allow the guest to play with any other
bit apart from INTx disable and memory and IO decoding on the command
register.
Thanks, Roger.
