On Fri, 5 Jan 2024, Jiqian Chen wrote:
> Some type of domain don't have PIRQ, like PVH, current
> implementation is not suitable for those domain.
>
> When passthrough a device to guest on PVH dom0, this
> pci_add_dm_done->XEN_DOMCTL_irq_permission will failed
> at domain_pirq_to_irq.
>
> So, change it to use gsi to grant/revoke irq permission.
> And change the caller of XEN_DOMCTL_irq_permission to
> pass gsi to it instead of pirq.
>
> Co-developed-by: Huang Rui <ray.hu...@amd.com>
> Signed-off-by: Jiqian Chen <jiqian.c...@amd.com>
I realize there is no explanation or comment right now, but I think this
change would benefit from a in-code comment in xen/include/public/domctl.h
E.g.:
/* XEN_DOMCTL_irq_permission */
struct xen_domctl_irq_permission {
uint32_t pirq; /* pirq is the GSI on x86 */
uint8_t allow_access; /* flag to specify enable/disable of IRQ access */
uint8_t pad[3];
};
> ---
> tools/libs/light/libxl_pci.c | 6 ++++--
> tools/libs/light/libxl_x86.c | 5 ++++-
> xen/common/domctl.c | 12 ++++++++++--
> 3 files changed, 18 insertions(+), 5 deletions(-)
>
> diff --git a/tools/libs/light/libxl_pci.c b/tools/libs/light/libxl_pci.c
> index 96cb4da0794e..e1341d1e9850 100644
> --- a/tools/libs/light/libxl_pci.c
> +++ b/tools/libs/light/libxl_pci.c
> @@ -1418,6 +1418,7 @@ static void pci_add_dm_done(libxl__egc *egc,
> unsigned long long start, end, flags, size;
> int irq, i;
> int r;
> + int gsi;
> uint32_t flag = XEN_DOMCTL_DEV_RDM_RELAXED;
> uint32_t domainid = domid;
> bool isstubdom = libxl_is_stubdom(ctx, domid, &domainid);
> @@ -1486,6 +1487,7 @@ static void pci_add_dm_done(libxl__egc *egc,
> goto out_no_irq;
> }
> if ((fscanf(f, "%u", &irq) == 1) && irq) {
> + gsi = irq;
A question for Roger and Jan: are we always guaranteed that gsi == irq
(also in the PV case)?
Also I don't think we necessarily need the gsi local variable, I would
just add an in-code comment below...
> r = xc_physdev_map_pirq(ctx->xch, domid, irq, &irq);
> if (r < 0) {
> LOGED(ERROR, domainid, "xc_physdev_map_pirq irq=%d (error=%d)",
> @@ -1494,10 +1496,10 @@ static void pci_add_dm_done(libxl__egc *egc,
> rc = ERROR_FAIL;
> goto out;
> }
... like this:
/* xc_domain_irq_permission takes a gsi, here we assume irq == gsi */
r = xc_domain_irq_permission(ctx->xch, domid, irq, 1);
> - r = xc_domain_irq_permission(ctx->xch, domid, irq, 1);
> + r = xc_domain_irq_permission(ctx->xch, domid, gsi, 1);
> if (r < 0) {
> LOGED(ERROR, domainid,
> - "xc_domain_irq_permission irq=%d (error=%d)", irq, r);
> + "xc_domain_irq_permission irq=%d (error=%d)", gsi, r);
> fclose(f);
> rc = ERROR_FAIL;
> goto out;
> diff --git a/tools/libs/light/libxl_x86.c b/tools/libs/light/libxl_x86.c
> index d16573e72cd4..88ad50cf6360 100644
> --- a/tools/libs/light/libxl_x86.c
> +++ b/tools/libs/light/libxl_x86.c
> @@ -654,12 +654,15 @@ out:
> int libxl__arch_domain_map_irq(libxl__gc *gc, uint32_t domid, int irq)
you could just rename the int irq parameter to int gsi ?
> {
> int ret;
> + int gsi;
> +
> + gsi = irq;
>
> ret = xc_physdev_map_pirq(CTX->xch, domid, irq, &irq);
> if (ret)
> return ret;
>
> - ret = xc_domain_irq_permission(CTX->xch, domid, irq, 1);
> + ret = xc_domain_irq_permission(CTX->xch, domid, gsi, 1);
> return ret;
> }
> diff --git a/xen/common/domctl.c b/xen/common/domctl.c
> index f5a71ee5f78d..eeb975bd0194 100644
> --- a/xen/common/domctl.c
> +++ b/xen/common/domctl.c
> @@ -653,12 +653,20 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t)
> u_domctl)
> unsigned int pirq = op->u.irq_permission.pirq, irq;
> int allow = op->u.irq_permission.allow_access;
here we could benefit from renaming pirq to gsi, at least it becomes
clear:
unsigned int gsi = op->u.irq_permission.pirq, irq;
> - if ( pirq >= current->domain->nr_pirqs )
> + if ( pirq >= nr_irqs_gsi )
> {
> ret = -EINVAL;
> break;
> }
> - irq = pirq_access_permitted(current->domain, pirq);
> +
> + if ( irq_access_permitted(current->domain, pirq) )
> + irq = pirq;
> + else
> + {
> + ret = -EPERM;
> + break;
> + }
> +
> if ( !irq || xsm_irq_permission(XSM_HOOK, d, irq, allow) )
> ret = -EPERM;
> else if ( allow )
> --
> 2.34.1
>
