On Mon, Apr 26, 2021 at 05:21:27PM +0100, Rahul Singh wrote:
> MSI code that implements MSI functionality to support MSI within XEN is
> not usable on ARM. Move the code under CONFIG_PCI_MSI_INTERCEPT flag to
> gate the code for ARM.
>
> Currently, we have no idea how MSI functionality will be supported for
> other architecture therefore we have decided to move the code under
> CONFIG_PCI_MSI_INTERCEPT. We know this is not the right flag to gate the
> code but to avoid an extra flag we decided to use this.
>
> No functional change intended.
>
> Signed-off-by: Rahul Singh <rahul.si...@arm.com>
I think this is fine, as we don't really want to add another Kconfig
option (ie: CONFIG_PCI_MSI) for just the non explicitly intercept MSI
code.
Reviewed-by: Roger Pau Monné <roger....@citrix.com>
Some nits below...
> ---
> Changes since v2:
> - This patch is added in this version.
> ---
> xen/drivers/passthrough/msi-intercept.c | 41 +++++++++++++++++++++++++
> xen/drivers/passthrough/pci.c | 34 ++++----------------
> xen/include/xen/msi-intercept.h | 7 +++++
> xen/include/xen/pci.h | 11 ++++---
> 4 files changed, 61 insertions(+), 32 deletions(-)
>
> diff --git a/xen/drivers/passthrough/msi-intercept.c
> b/xen/drivers/passthrough/msi-intercept.c
> index 1edae6d4e8..33ab71514d 100644
> --- a/xen/drivers/passthrough/msi-intercept.c
> +++ b/xen/drivers/passthrough/msi-intercept.c
> @@ -19,6 +19,47 @@
> #include <asm/msi.h>
> #include <asm/hvm/io.h>
>
> +int pdev_msi_init(struct pci_dev *pdev)
> +{
> + unsigned int pos;
> +
> + INIT_LIST_HEAD(&pdev->msi_list);
> +
> + pos = pci_find_cap_offset(pdev->seg, pdev->bus, PCI_SLOT(pdev->devfn),
> + PCI_FUNC(pdev->devfn), PCI_CAP_ID_MSI);
> + if ( pos )
> + {
> + uint16_t ctrl = pci_conf_read16(pdev->sbdf, msi_control_reg(pos));
> +
> + pdev->msi_maxvec = multi_msi_capable(ctrl);
> + }
> +
> + pos = pci_find_cap_offset(pdev->seg, pdev->bus, PCI_SLOT(pdev->devfn),
> + PCI_FUNC(pdev->devfn), PCI_CAP_ID_MSIX);
> + if ( pos )
> + {
> + struct arch_msix *msix = xzalloc(struct arch_msix);
> + uint16_t ctrl;
> +
> + if ( !msix )
> + return -ENOMEM;
> +
> + spin_lock_init(&msix->table_lock);
> +
> + ctrl = pci_conf_read16(pdev->sbdf, msix_control_reg(pos));
> + msix->nr_entries = msix_table_size(ctrl);
> +
> + pdev->msix = msix;
> + }
> +
> + return 0;
> +}
> +
> +void pdev_msi_deinit(struct pci_dev *pdev)
> +{
> + XFREE(pdev->msix);
> +}
> +
> int pdev_msix_assign(struct domain *d, struct pci_dev *pdev)
> {
> int rc;
> diff --git a/xen/drivers/passthrough/pci.c b/xen/drivers/passthrough/pci.c
> index 298be21b5b..b1e3c711ad 100644
> --- a/xen/drivers/passthrough/pci.c
> +++ b/xen/drivers/passthrough/pci.c
> @@ -314,6 +314,7 @@ static struct pci_dev *alloc_pdev(struct pci_seg *pseg,
> u8 bus, u8 devfn)
> {
> struct pci_dev *pdev;
> unsigned int pos;
> + int rc;
>
> list_for_each_entry ( pdev, &pseg->alldevs_list, alldevs_list )
> if ( pdev->bus == bus && pdev->devfn == devfn )
> @@ -327,35 +328,12 @@ static struct pci_dev *alloc_pdev(struct pci_seg *pseg,
> u8 bus, u8 devfn)
> *((u8*) &pdev->bus) = bus;
> *((u8*) &pdev->devfn) = devfn;
> pdev->domain = NULL;
> - INIT_LIST_HEAD(&pdev->msi_list);
> -
> - pos = pci_find_cap_offset(pseg->nr, bus, PCI_SLOT(devfn),
> PCI_FUNC(devfn),
> - PCI_CAP_ID_MSI);
> - if ( pos )
> - {
> - uint16_t ctrl = pci_conf_read16(pdev->sbdf, msi_control_reg(pos));
>
> - pdev->msi_maxvec = multi_msi_capable(ctrl);
> - }
> -
> - pos = pci_find_cap_offset(pseg->nr, bus, PCI_SLOT(devfn),
> PCI_FUNC(devfn),
> - PCI_CAP_ID_MSIX);
> - if ( pos )
> + rc = pdev_msi_init(pdev);
> + if ( rc )
> {
> - struct arch_msix *msix = xzalloc(struct arch_msix);
> - uint16_t ctrl;
> -
> - if ( !msix )
> - {
> - xfree(pdev);
> - return NULL;
> - }
> - spin_lock_init(&msix->table_lock);
> -
> - ctrl = pci_conf_read16(pdev->sbdf, msix_control_reg(pos));
> - msix->nr_entries = msix_table_size(ctrl);
> -
> - pdev->msix = msix;
> + XFREE(pdev);
There's no need to use XFREE here, plain xfree is fine since pdev is a
local variable so makes no sense to assign to NULL before returning.
> + return NULL;
> }
>
> list_add(&pdev->alldevs_list, &pseg->alldevs_list);
> @@ -449,7 +427,7 @@ static void free_pdev(struct pci_seg *pseg, struct
> pci_dev *pdev)
> }
>
> list_del(&pdev->alldevs_list);
> - xfree(pdev->msix);
> + pdev_msi_deinit(pdev);
> xfree(pdev);
> }
>
> diff --git a/xen/include/xen/msi-intercept.h b/xen/include/xen/msi-intercept.h
> index 77c105e286..38ff7a09e1 100644
> --- a/xen/include/xen/msi-intercept.h
> +++ b/xen/include/xen/msi-intercept.h
> @@ -21,16 +21,23 @@
>
> #include <asm/msi.h>
>
> +int pdev_msi_init(struct pci_dev *pdev);
> +void pdev_msi_deinit(struct pci_dev *pdev);
> int pdev_msix_assign(struct domain *d, struct pci_dev *pdev);
> void pdev_dump_msi(const struct pci_dev *pdev);
>
> #else /* !CONFIG_PCI_MSI_INTERCEPT */
> +static inline int pdev_msi_init(struct pci_dev *pdev)
> +{
> + return 0;
> +}
>
> static inline int pdev_msix_assign(struct domain *d, struct pci_dev *pdev)
> {
> return 0;
> }
>
> +static inline void pdev_msi_deinit(struct pci_dev *pdev) {}
> static inline void pdev_dump_msi(const struct pci_dev *pdev) {}
> static inline void pci_cleanup_msi(struct pci_dev *pdev) {}
>
> diff --git a/xen/include/xen/pci.h b/xen/include/xen/pci.h
> index 8e3d4d9454..f5b57270be 100644
> --- a/xen/include/xen/pci.h
> +++ b/xen/include/xen/pci.h
> @@ -79,10 +79,6 @@ struct pci_dev {
> struct list_head alldevs_list;
> struct list_head domain_list;
>
> - struct list_head msi_list;
> -
> - struct arch_msix *msix;
> -
> struct domain *domain;
>
> const union {
> @@ -94,7 +90,14 @@ struct pci_dev {
> pci_sbdf_t sbdf;
> };
>
> +#ifdef CONFIG_PCI_MSI_INTERCEPT
> + struct list_head msi_list;
> +
> + struct arch_msix *msix;
> +
> uint8_t msi_maxvec;
> +#endif
This seems to introduce some padding between the sbdf and the msi_list
field. I guess that's better than having two different
CONFIG_PCI_MSI_INTERCEPT guarded regions?
Thanks, Roger.
