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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v5 24/30] ARM: vITS: handle MOVI command
On Thu, 6 Apr 2017, Andre Przywara wrote:
> On 06/04/17 01:47, Stefano Stabellini wrote:
> > On Thu, 6 Apr 2017, Andre Przywara wrote:
> >> The MOVI command moves the interrupt affinity from one redistributor
> >> (read: VCPU) to another.
> >> For now migration of "live" LPIs is not yet implemented, but we store
> >> the changed affinity in the host LPI structure and in our virtual ITTE.
> >>
> >> Signed-off-by: Andre Przywara <andre.przywara@xxxxxxx>
> >> ---
> >> xen/arch/arm/gic-v3-its.c | 24 ++++++++++++++++++++
> >> xen/arch/arm/gic-v3-lpi.c | 15 +++++++++++++
> >> xen/arch/arm/vgic-v3-its.c | 47
> >> ++++++++++++++++++++++++++++++++++++++++
> >> xen/include/asm-arm/gic_v3_its.h | 4 ++++
> >> 4 files changed, 90 insertions(+)
> >>
> >> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
> >> index d970119..a57e63a 100644
> >> --- a/xen/arch/arm/gic-v3-its.c
> >> +++ b/xen/arch/arm/gic-v3-its.c
> >> @@ -851,6 +851,30 @@ struct pending_irq *gicv3_assign_guest_event(struct
> >> domain *d,
> >> return pirq;
> >> }
> >>
> >> +/* Changes the target VCPU for a given host LPI assigned to a domain. */
> >> +int gicv3_lpi_change_vcpu(struct domain *d, paddr_t vdoorbell,
> >> + uint32_t vdevid, uint32_t veventid,
> >> + unsigned int vcpu_id)
> >> +{
> >> + uint32_t host_lpi;
> >> + struct its_devices *dev;
> >> +
> >> + spin_lock(&d->arch.vgic.its_devices_lock);
> >> + dev = get_its_device(d, vdoorbell, vdevid);
> >> + if ( dev )
> >> + host_lpi = get_host_lpi(dev, veventid);
> >> + else
> >> + host_lpi = 0;
> >> + spin_unlock(&d->arch.vgic.its_devices_lock);
> >> +
> >> + if ( !host_lpi )
> >> + return -ENOENT;
> >> +
> >> + gicv3_lpi_update_host_vcpuid(host_lpi, vcpu_id);
> >
> > we need to call vgic_migrate_irq
>
> Mmmh, are you sure? The very first statement there reads:
>
> /* nothing to do for virtual interrupts */
> if ( p->desc == NULL )
> return;
>
> Also my understanding of this command is that it only affects future
> MSIs, so ITS translations. If an MSI has already been translated to a
> certain redistributor and the ITS signaled it already, this command has
> no effect on this particular one.
> Also we don't care about benign races, so if this command comes in a tad
> to late for a just happening MSI, this is the same problem on real hardware.
It is more complicated than I thought. I would add a in-code comment
here like this:
TODO: we do not change physical irq affinity, in response to a virtual
movi command. In other words, the physical LPI will still be delivered
to the same pcpu.
In addition to the comment, I wouldn't mind if also a warning was
printed (with gdprintk).
> >> + return 0;
> >> +}
> >> +
> >> /* Scan the DT for any ITS nodes and create a list of host ITSes out of
> >> it. */
> >> void gicv3_its_dt_init(const struct dt_device_node *node)
> >> {
> >> diff --git a/xen/arch/arm/gic-v3-lpi.c b/xen/arch/arm/gic-v3-lpi.c
> >> index c997ed5..b9960aa 100644
> >> --- a/xen/arch/arm/gic-v3-lpi.c
> >> +++ b/xen/arch/arm/gic-v3-lpi.c
> >> @@ -234,6 +234,21 @@ void gicv3_lpi_update_host_entry(uint32_t host_lpi,
> >> int domain_id,
> >> write_u64_atomic(&hlpip->data, hlpi.data);
> >> }
> >>
> >> +int gicv3_lpi_update_host_vcpuid(uint32_t host_lpi, unsigned int vcpu_id)
> >> +{
> >> + union host_lpi *hlpip;
> >> +
> >> + ASSERT(host_lpi >= LPI_OFFSET);
> >> +
> >> + host_lpi -= LPI_OFFSET;
> >> +
> >> + hlpip = &lpi_data.host_lpis[host_lpi / HOST_LPIS_PER_PAGE][host_lpi %
> >> HOST_LPIS_PER_PAGE];
> >> +
> >> + write_u16_atomic(&hlpip->vcpu_id, vcpu_id);
> >> +
> >> + return 0;
> >> +}
> >> +
> >> static int gicv3_lpi_allocate_pendtable(uint64_t *reg)
> >> {
> >> uint64_t val;
> >> diff --git a/xen/arch/arm/vgic-v3-its.c b/xen/arch/arm/vgic-v3-its.c
> >> index 079dd44..6afb915 100644
> >> --- a/xen/arch/arm/vgic-v3-its.c
> >> +++ b/xen/arch/arm/vgic-v3-its.c
> >> @@ -508,6 +508,47 @@ static int its_handle_mapti(struct virt_its *its,
> >> uint64_t *cmdptr)
> >> return 0;
> >> }
> >>
> >> +static int its_handle_movi(struct virt_its *its, uint64_t *cmdptr)
> >> +{
> >> + uint32_t devid = its_cmd_get_deviceid(cmdptr);
> >> + uint32_t eventid = its_cmd_get_id(cmdptr);
> >> + int collid = its_cmd_get_collection(cmdptr);
> >> + struct pending_irq *p;
> >> + struct vcpu *vcpu;
> >> + uint32_t vlpi;
> >> + int ret = -1;
> >> +
> >> + spin_lock(&its->its_lock);
> >> + /* Check for a mapped LPI and get the LPI number. */
> >> + if ( !read_itte_locked(its, devid, eventid, &vcpu, &vlpi) )
> >> + goto out_unlock;
> >> +
> >> + /* Check the new collection ID and get the new VCPU pointer */
> >> + vcpu = get_vcpu_from_collection(its, collid);
> >> + if ( !vcpu )
> >> + goto out_unlock;
> >> +
> >> + /* Update our cached vcpu_id in the pending_irq. */
> >> + p = its->d->arch.vgic.handler->lpi_to_pending(its->d, vlpi);
> >> + p->vcpu_id = vcpu->vcpu_id;
> >> +
> >> + /* Now store the new collection in the translation table. */
> >> + if ( !write_itte_locked(its, devid, eventid, collid, vlpi, &vcpu) )
> >> + goto out_unlock;
> >> +
> >> + spin_unlock(&its->its_lock);
> >> +
> >> + /* TODO: lookup currently-in-guest virtual IRQs and migrate them? */
> >> +
> >> + return gicv3_lpi_change_vcpu(its->d, its->doorbell_address,
> >> + devid, eventid, vcpu->vcpu_id);
> >> +
> >> +out_unlock:
> >> + spin_unlock(&its->its_lock);
> >> +
> >> + return ret;
> >> +}
> >> +
> >> #define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12)
> >>
> >> /*
> >> @@ -552,6 +593,12 @@ static int vgic_its_handle_cmds(struct domain *d,
> >> struct virt_its *its)
> >> case GITS_CMD_MAPTI:
> >> ret = its_handle_mapti(its, command);
> >> break;
> >> + case GITS_CMD_MOVALL:
> >> + gdprintk(XENLOG_G_INFO, "ITS: ignoring MOVALL command\n");
> >> + break;
> >> + case GITS_CMD_MOVI:
> >> + ret = its_handle_movi(its, command);
> >> + break;
> >> case GITS_CMD_SYNC:
> >> /* We handle ITS commands synchronously, so we ignore SYNC. */
> >> break;
> >> diff --git a/xen/include/asm-arm/gic_v3_its.h
> >> b/xen/include/asm-arm/gic_v3_its.h
> >> index 30aa1ef..daae143 100644
> >> --- a/xen/include/asm-arm/gic_v3_its.h
> >> +++ b/xen/include/asm-arm/gic_v3_its.h
> >> @@ -177,8 +177,12 @@ void gicv3_free_host_lpi_block(uint32_t first_lpi);
> >> struct pending_irq *gicv3_assign_guest_event(struct domain *d, paddr_t
> >> doorbell,
> >> uint32_t devid, uint32_t
> >> eventid,
> >> struct vcpu *v, uint32_t
> >> virt_lpi);
> >> +int gicv3_lpi_change_vcpu(struct domain *d, paddr_t doorbell,
> >> + uint32_t devid, uint32_t eventid,
> >> + unsigned int vcpu_id);
> >> void gicv3_lpi_update_host_entry(uint32_t host_lpi, int domain_id,
> >> unsigned int vcpu_id, uint32_t virt_lpi);
> >> +int gicv3_lpi_update_host_vcpuid(uint32_t host_lpi, unsigned int vcpu_id);
> >>
> >> #else
> >>
> >> --
> >> 2.8.2
> >>
>
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