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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v8 21/27] ARM: vITS: handle MOVI command
Hi,
On 12/04/17 17:59, Julien Grall wrote:
> Hi Andre,
>
> On 12/04/17 01:44, 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 | 57
>> ++++++++++++++++++++++++++++++++++++++++
>> xen/include/asm-arm/gic_v3_its.h | 4 +++
>> 4 files changed, 100 insertions(+)
>>
>> diff --git a/xen/arch/arm/gic-v3-its.c b/xen/arch/arm/gic-v3-its.c
>> index fa1f2d5..1a08d43 100644
>> --- a/xen/arch/arm/gic-v3-its.c
>> +++ b/xen/arch/arm/gic-v3-its.c
>> @@ -895,6 +895,30 @@ 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_device *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);
>
> In v5, Stefano suggested to add a TODO here:
>
> 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.
>
> He was already suggested to print a warning (with gdprintk).
I added a TODO, but don't think a warning is a good idea. There is no
*requirement* to move the physical affinity along with the virtual one,
so printing a warning for something we know will happen seems a bit odd.
Cheers,
Andre.
> I see none of them, where are they?
>
>> +
>> + 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 d427539..6af5ad9 100644
>> --- a/xen/arch/arm/gic-v3-lpi.c
>> +++ b/xen/arch/arm/gic-v3-lpi.c
>> @@ -225,6 +225,21 @@ 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 0765810..be9de08 100644
>> --- a/xen/arch/arm/vgic-v3-its.c
>> +++ b/xen/arch/arm/vgic-v3-its.c
>> @@ -647,6 +647,57 @@ out_remove_mapping:
>> return ret;
>> }
>>
>> +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);
>
> why collid is signed? From the spec, this should be uint16_t.
>
>> + unsigned long flags;
>> + struct pending_irq *p;
>> + struct vcpu *ovcpu, *nvcpu;
>> + 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, &ovcpu, &vlpi) )
>> + goto out_unlock;
>> +
>> + if ( vlpi == INVALID_LPI )
>> + {
>> + spin_unlock(&its->its_lock);
>> + return -1;
>> + }
>> +
>> + /* Check the new collection ID and get the new VCPU pointer */
>> + nvcpu = get_vcpu_from_collection(its, collid);
>> + if ( !nvcpu )
>> + goto out_unlock;
>> +
>> + spin_lock_irqsave(&ovcpu->arch.vgic.lock, flags);
>> +
>> + /* Update our cached vcpu_id in the pending_irq. */
>> + p = its->d->arch.vgic.handler->lpi_to_pending(its->d, vlpi);
>
> So the table could be crafted by the guest before enable the LPI in
> order to show a valid LPI. This would lead to returning NULL here as it
> is not mapped. And crash Xen.
>
>> + p->lpi_vcpu_id = nvcpu->vcpu_id;
>> +
>> + /* Now store the new collection in the translation table. */
>> + if ( !write_itte_locked(its, devid, eventid, collid, vlpi, &nvcpu) )
>> + goto out_unlock;
>> +
>> + spin_unlock_irqrestore(&ovcpu->arch.vgic.lock, flags);
>> + 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, nvcpu->vcpu_id);
>> +
>> +out_unlock:
>> + spin_unlock(&its->its_lock);
>> +
>> + return ret;
>> +}
>> +
>> #define ITS_CMD_BUFFER_SIZE(baser) ((((baser) & 0xff) + 1) << 12)
>> #define ITS_CMD_OFFSET(reg) ((reg) & GENMASK(19, 5))
>>
>> @@ -692,6 +743,12 @@ 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");
>
> Again, I'd like some explanation in the commit message why MOVALL is not
> implemented and a TODO in the code.
>
>> + 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 7b16aeb..ee69e9b 100644
>> --- a/xen/include/asm-arm/gic_v3_its.h
>> +++ b/xen/include/asm-arm/gic_v3_its.h
>> @@ -175,8 +175,12 @@ int gicv3_remove_guest_event(struct domain *d,
>> paddr_t vdoorbell_address,
>> 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
>>
>>
>
> Cheers,
>
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