On 2024/1/6 09:08, Stefano Stabellini wrote:
> 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];
> };
Will add this comment in next version, thanks.
>
>
>> ---
>> 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...
Here pass the pointer of irq to xc_physdev_map_pirq, and that function will
assign the value of pirq to irq on Xen side, so after calling
xc_physdev_map_pirq, the value of irq isn't the original value, we need a local
variable to record the original value.
>
>
>> 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);
Will add this comment in next version, thanks.
>
>
>> - 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 ?
No, the same reason as above.
>
>
>> {
>> 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;
Thank you, I will rename it in next version.
>
>
>> - 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
>>
--
Best regards,
Jiqian Chen.
