From: eric.auger@linaro.org (Eric Auger)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 12/15] KVM: arm64: sync LPI configuration and pending tables
Date: Mon, 31 Aug 2015 11:51:33 +0200 [thread overview]
Message-ID: <55E423A5.9080703@linaro.org> (raw)
In-Reply-To: <55DC8DF5.3010303@arm.com>
On 08/25/2015 05:47 PM, Andre Przywara wrote:
> Hi Eric,
>
> On 14/08/15 13:35, Eric Auger wrote:
>> On 08/14/2015 01:58 PM, Eric Auger wrote:
>>> On 07/10/2015 04:21 PM, Andre Przywara wrote:
>>>> The LPI configuration and pending tables of the GICv3 LPIs are held
>>>> in tables in (guest) memory. To achieve reasonable performance, we
>>>> cache this data in our own data structures, so we need to sync those
>>>> two views from time to time. This behaviour is well described in the
>>>> GICv3 spec and is also exercised by hardware, so the sync points are
>>>> well known.
>>>>
>>>> Provide functions that read the guest memory and store the
>>>> information from the configuration and pending tables in the kernel.
>>>>
>>>> Signed-off-by: Andre Przywara <andre.przywara@arm.com>
>>>> ---
>>> would help to have change log between v1 -> v2 (valid for the whole series)
>>>> include/kvm/arm_vgic.h | 2 +
>>>> virt/kvm/arm/its-emul.c | 124 ++++++++++++++++++++++++++++++++++++++++++++++++
>>>> virt/kvm/arm/its-emul.h | 3 ++
>>>> 3 files changed, 129 insertions(+)
>>>>
>>>> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
>>>> index 2a67a10..323c33a 100644
>>>> --- a/include/kvm/arm_vgic.h
>>>> +++ b/include/kvm/arm_vgic.h
>>>> @@ -167,6 +167,8 @@ struct vgic_its {
>>>> int cwriter;
>>>> struct list_head device_list;
>>>> struct list_head collection_list;
>>>> + /* memory used for buffering guest's memory */
>>>> + void *buffer_page;
>>>> };
>>>>
>>>> struct vgic_dist {
>>>> diff --git a/virt/kvm/arm/its-emul.c b/virt/kvm/arm/its-emul.c
>>>> index b9c40d7..05245cb 100644
>>>> --- a/virt/kvm/arm/its-emul.c
>>>> +++ b/virt/kvm/arm/its-emul.c
>>>> @@ -50,6 +50,7 @@ struct its_itte {
>>>> struct its_collection *collection;
>>>> u32 lpi;
>>>> u32 event_id;
>>>> + u8 priority;
>>>> bool enabled;
>>>> unsigned long *pending;
>>>> };
>>>> @@ -70,8 +71,124 @@ static struct its_itte *find_itte_by_lpi(struct kvm *kvm, int lpi)
>>>> return NULL;
>>>> }
>>>>
>>>> +#define LPI_PROP_ENABLE_BIT(p) ((p) & LPI_PROP_ENABLED)
>>>> +#define LPI_PROP_PRIORITY(p) ((p) & 0xfc)
>>>> +
>>>> +/* stores the priority and enable bit for a given LPI */
>>>> +static void update_lpi_config(struct kvm *kvm, struct its_itte *itte, u8 prop)
>>>> +{
>>>> + itte->priority = LPI_PROP_PRIORITY(prop);
>>>> + itte->enabled = LPI_PROP_ENABLE_BIT(prop);
>>>> +}
>>>> +
>>>> +#define GIC_LPI_OFFSET 8192
>>>> +
>>>> +/* We scan the table in chunks the size of the smallest page size */
>>> 4kB chunks?
>>>> +#define CHUNK_SIZE 4096U
>>>> +
>>>> #define BASER_BASE_ADDRESS(x) ((x) & 0xfffffffff000ULL)
>>>>
>>>> +static int nr_idbits_propbase(u64 propbaser)
>>>> +{
>>>> + int nr_idbits = (1U << (propbaser & 0x1f)) + 1;
>>>> +
>>>> + return max(nr_idbits, INTERRUPT_ID_BITS_ITS);
>>>> +}
>>>> +
>>>> +/*
>>>> + * Scan the whole LPI configuration table and put the LPI configuration
>>>> + * data in our own data structures. This relies on the LPI being
>>>> + * mapped before.
>>>> + */
>>>> +static bool its_update_lpis_configuration(struct kvm *kvm)
>>>> +{
>>>> + struct vgic_dist *dist = &kvm->arch.vgic;
>>>> + u8 *prop = dist->its.buffer_page;
>>>> + u32 tsize;
>>>> + gpa_t propbase;
>>>> + int lpi = GIC_LPI_OFFSET;
>>>> + struct its_itte *itte;
>>>> + struct its_device *device;
>>>> + int ret;
>>>> +
>>>> + propbase = BASER_BASE_ADDRESS(dist->propbaser);
>>>> + tsize = nr_idbits_propbase(dist->propbaser);
>>>> +
>>>> + while (tsize > 0) {
>>>> + int chunksize = min(tsize, CHUNK_SIZE);
>>>> +
>>>> + ret = kvm_read_guest(kvm, propbase, prop, chunksize);
>>> I think you still have the spin_lock issue since if my understanding is
>>> correct this is called from
>>> vgic_handle_mmio_access/vcall_range_handler/gic_enable_lpis
>>> where vgic_handle_mmio_access. Or does it take another path?
>>>
>>> Shouldn't we create a new kvm_io_device to avoid holding the dist lock?
>>
>> Sorry I forgot it was the case already. But currently we always register
>> the same io ops (registration entry point being
>> vgic_register_kvm_io_dev) and maybe we should have separate dispatcher
>> function for dist, redit and its?
>
> What would be the idea behind it? To have separate locks for each? I
> don't think that will work, as some ITS functions are called from GICv3
> register handler functions which manipulate members of the distributor
> structure.
Yes it was the idea.
So I am more in favour of dropping the dist lock in these
> cases before handing off execution to ITS specific functions.
OK. Let's see how the refactoring looks like then
Cheers
Eric
>
> Cheers,
> Andre.
>
next prev parent reply other threads:[~2015-08-31 9:51 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-07-10 14:21 [PATCH v2 00/15] KVM: arm64: GICv3 ITS emulation Andre Przywara
2015-07-10 14:21 ` [PATCH v2 01/15] KVM: arm/arm64: VGIC: don't track used LRs in the distributor Andre Przywara
2015-08-12 9:01 ` Eric Auger
2015-08-24 16:33 ` Andre Przywara
2015-08-31 8:42 ` Eric Auger
2015-09-02 9:00 ` Andre Przywara
2015-10-02 9:55 ` Pavel Fedin
2015-10-02 10:32 ` Andre Przywara
2015-10-02 10:39 ` Pavel Fedin
2015-10-02 12:39 ` Pavel Fedin
2015-10-02 12:49 ` Andre Przywara
2015-07-10 14:21 ` [PATCH v2 02/15] KVM: extend struct kvm_msi to hold a 32-bit device ID Andre Przywara
2015-07-10 14:21 ` [PATCH v2 03/15] KVM: arm/arm64: add emulation model specific destroy function Andre Przywara
2015-07-10 14:21 ` [PATCH v2 04/15] KVM: arm/arm64: extend arch CAP checks to allow per-VM capabilities Andre Przywara
2015-08-12 12:26 ` Eric Auger
2015-07-10 14:21 ` [PATCH v2 05/15] KVM: arm/arm64: make GIC frame address initialization model specific Andre Przywara
2015-08-12 13:02 ` Eric Auger
2015-08-24 17:24 ` Andre Przywara
2015-08-31 9:31 ` Eric Auger
2015-07-10 14:21 ` [PATCH v2 06/15] KVM: arm64: Introduce new MMIO region for the ITS base address Andre Przywara
2015-08-13 12:17 ` Eric Auger
2015-07-10 14:21 ` [PATCH v2 07/15] KVM: arm64: handle ITS related GICv3 redistributor registers Andre Przywara
2015-08-13 12:17 ` Eric Auger
2015-08-24 18:08 ` Andre Przywara
2015-07-10 14:21 ` [PATCH v2 08/15] KVM: arm64: introduce ITS emulation file with stub functions Andre Przywara
2015-08-13 12:48 ` Eric Auger
2015-08-25 9:39 ` Andre Przywara
2015-07-10 14:21 ` [PATCH v2 09/15] KVM: arm64: implement basic ITS register handlers Andre Przywara
2015-08-13 15:25 ` Eric Auger
2015-08-25 10:23 ` Andre Przywara
2015-10-02 7:51 ` Pavel Fedin
2015-07-10 14:21 ` [PATCH v2 10/15] KVM: arm64: add data structures to model ITS interrupt translation Andre Przywara
2015-08-13 15:46 ` Eric Auger
2015-08-25 11:15 ` Andre Przywara
2015-08-27 14:16 ` Eric Auger
2015-07-10 14:21 ` [PATCH v2 11/15] KVM: arm64: handle pending bit for LPIs in ITS emulation Andre Przywara
2015-08-14 11:58 ` Eric Auger
2015-08-25 14:34 ` Andre Przywara
2015-08-31 9:45 ` Eric Auger
2015-10-07 8:39 ` Pavel Fedin
2015-10-07 19:53 ` Christoffer Dall
2015-07-10 14:21 ` [PATCH v2 12/15] KVM: arm64: sync LPI configuration and pending tables Andre Przywara
2015-08-14 11:58 ` Eric Auger
2015-08-14 12:35 ` Eric Auger
2015-08-25 15:47 ` Andre Przywara
2015-08-31 9:51 ` Eric Auger [this message]
2015-08-25 15:27 ` Andre Przywara
2015-08-31 9:47 ` Eric Auger
2015-07-10 14:21 ` [PATCH v2 13/15] KVM: arm64: implement ITS command queue command handlers Andre Przywara
2015-08-17 13:33 ` Eric Auger
2015-10-07 14:54 ` Andre Przywara
2015-07-10 14:21 ` [PATCH v2 14/15] KVM: arm64: implement MSI injection in ITS emulation Andre Przywara
2015-07-31 13:22 ` Eric Auger
2015-08-02 20:20 ` Andre Przywara
2015-08-03 6:41 ` Pavel Fedin
2015-08-03 9:07 ` Eric Auger
2015-08-03 9:16 ` Pavel Fedin
2015-08-03 15:37 ` Eric Auger
2015-08-03 17:06 ` Marc Zyngier
2015-08-04 6:53 ` Pavel Fedin
2015-08-24 14:14 ` Andre Przywara
2015-08-17 13:44 ` Eric Auger
2015-07-10 14:21 ` [PATCH v2 15/15] KVM: arm64: enable ITS emulation as a virtual MSI controller Andre Przywara
2015-07-15 9:10 ` Pavel Fedin
2015-07-15 9:52 ` Andre Przywara
2015-07-15 10:01 ` Pavel Fedin
2015-07-15 12:02 ` [PATCH v2 00/15] KVM: arm64: GICv3 ITS emulation Pavel Fedin
2015-09-24 11:18 ` Pavel Fedin
2015-09-24 11:35 ` Andre Przywara
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