On 3/18/19 4:23 AM, David Gibson wrote:
> On Fri, Mar 15, 2019 at 01:05:58PM +0100, Cédric Le Goater wrote:
>> These controls will be used by the H_INT_SET_QUEUE_CONFIG and
>> H_INT_GET_QUEUE_CONFIG hcalls from QEMU to configure the underlying
>> Event Queue in the XIVE IC. They will also be used to restore the
>> configuration of the XIVE EQs and to capture the internal run-time
>> state of the EQs. Both 'get' and 'set' rely on an OPAL call to access
>> the EQ toggle bit and EQ index which are updated by the XIVE IC when
>> event notifications are enqueued in the EQ.
>>
>> The value of the guest physical address of the event queue is saved in
>> the XIVE internal xive_q structure for later use. That is when
>> migration needs to mark the EQ pages dirty to capture a consistent
>> memory state of the VM.
>>
>> To be noted that H_INT_SET_QUEUE_CONFIG does not require the extra
>> OPAL call setting the EQ toggle bit and EQ index to configure the EQ,
>> but restoring the EQ state will.
>>
>> Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
>> ---
>>
>> Changes since v2 :
>>
>> - fixed comments on the KVM device attribute definitions
>> - fixed check on supported EQ size to restrict to 64K pages
>> - checked kvm_eq.flags that need to be zero
>> - removed the OPAL call when EQ qtoggle bit and index are zero.
>>
>> arch/powerpc/include/asm/xive.h | 2 +
>> arch/powerpc/include/uapi/asm/kvm.h | 21 ++
>> arch/powerpc/kvm/book3s_xive.h | 2 +
>> arch/powerpc/kvm/book3s_xive.c | 15 +-
>> arch/powerpc/kvm/book3s_xive_native.c | 232 +++++++++++++++++++++
>> Documentation/virtual/kvm/devices/xive.txt | 31 +++
>> 6 files changed, 297 insertions(+), 6 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/xive.h b/arch/powerpc/include/asm/xive.h
>> index b579a943407b..46891f321606 100644
>> --- a/arch/powerpc/include/asm/xive.h
>> +++ b/arch/powerpc/include/asm/xive.h
>> @@ -73,6 +73,8 @@ struct xive_q {
>> u32 esc_irq;
>> atomic_t count;
>> atomic_t pending_count;
>> + u64 guest_qpage;
>> + u32 guest_qsize;
>> };
>>
>> /* Global enable flags for the XIVE support */
>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
>> index 12bb01baf0ae..1cd728c87d7c 100644
>> --- a/arch/powerpc/include/uapi/asm/kvm.h
>> +++ b/arch/powerpc/include/uapi/asm/kvm.h
>> @@ -679,6 +679,7 @@ struct kvm_ppc_cpu_char {
>> #define KVM_DEV_XIVE_GRP_CTRL 1
>> #define KVM_DEV_XIVE_GRP_SOURCE 2 /* 64-bit source identifier */
>> #define KVM_DEV_XIVE_GRP_SOURCE_CONFIG 3 /* 64-bit source identifier */
>> +#define KVM_DEV_XIVE_GRP_EQ_CONFIG 4 /* 64-bit EQ identifier */
>>
>> /* Layout of 64-bit XIVE source attribute values */
>> #define KVM_XIVE_LEVEL_SENSITIVE (1ULL << 0)
>> @@ -694,4 +695,24 @@ struct kvm_ppc_cpu_char {
>> #define KVM_XIVE_SOURCE_EISN_SHIFT 33
>> #define KVM_XIVE_SOURCE_EISN_MASK 0xfffffffe00000000ULL
>>
>> +/* Layout of 64-bit EQ identifier */
>> +#define KVM_XIVE_EQ_PRIORITY_SHIFT 0
>> +#define KVM_XIVE_EQ_PRIORITY_MASK 0x7
>> +#define KVM_XIVE_EQ_SERVER_SHIFT 3
>> +#define KVM_XIVE_EQ_SERVER_MASK 0xfffffff8ULL
>> +
>> +/* Layout of EQ configuration values (64 bytes) */
>> +struct kvm_ppc_xive_eq {
>> + __u32 flags;
>> + __u32 qsize;
>> + __u64 qpage;
>> + __u32 qtoggle;
>> + __u32 qindex;
>> + __u8 pad[40];
>> +};
>> +
>> +#define KVM_XIVE_EQ_FLAG_ENABLED 0x00000001
>> +#define KVM_XIVE_EQ_FLAG_ALWAYS_NOTIFY 0x00000002
>> +#define KVM_XIVE_EQ_FLAG_ESCALATE 0x00000004
>> +
>> #endif /* __LINUX_KVM_POWERPC_H */
>> diff --git a/arch/powerpc/kvm/book3s_xive.h b/arch/powerpc/kvm/book3s_xive.h
>> index ae26fe653d98..622f594d93e1 100644
>> --- a/arch/powerpc/kvm/book3s_xive.h
>> +++ b/arch/powerpc/kvm/book3s_xive.h
>> @@ -272,6 +272,8 @@ struct kvmppc_xive_src_block *kvmppc_xive_create_src_block(
>> struct kvmppc_xive *xive, int irq);
>> void kvmppc_xive_free_sources(struct kvmppc_xive_src_block *sb);
>> int kvmppc_xive_select_target(struct kvm *kvm, u32 *server, u8 prio);
>> +int kvmppc_xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio,
>> + bool single_escalation);
>>
>> #endif /* CONFIG_KVM_XICS */
>> #endif /* _KVM_PPC_BOOK3S_XICS_H */
>> diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
>> index e09f3addffe5..c1b7aa7dbc28 100644
>> --- a/arch/powerpc/kvm/book3s_xive.c
>> +++ b/arch/powerpc/kvm/book3s_xive.c
>> @@ -166,7 +166,8 @@ static irqreturn_t xive_esc_irq(int irq, void *data)
>> return IRQ_HANDLED;
>> }
>>
>> -static int xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio)
>> +int kvmppc_xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio,
>> + bool single_escalation)
>> {
>> struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> struct xive_q *q = &xc->queues[prio];
>> @@ -185,7 +186,7 @@ static int xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio)
>> return -EIO;
>> }
>>
>> - if (xc->xive->single_escalation)
>> + if (single_escalation)
>> name = kasprintf(GFP_KERNEL, "kvm-%d-%d",
>> vcpu->kvm->arch.lpid, xc->server_num);
>> else
>> @@ -217,7 +218,7 @@ static int xive_attach_escalation(struct kvm_vcpu *vcpu, u8 prio)
>> * interrupt, thus leaving it effectively masked after
>> * it fires once.
>> */
>> - if (xc->xive->single_escalation) {
>> + if (single_escalation) {
>> struct irq_data *d = irq_get_irq_data(xc->esc_virq[prio]);
>> struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
>>
>> @@ -291,7 +292,8 @@ static int xive_check_provisioning(struct kvm *kvm, u8 prio)
>> continue;
>> rc = xive_provision_queue(vcpu, prio);
>> if (rc == 0 && !xive->single_escalation)
>> - xive_attach_escalation(vcpu, prio);
>> + kvmppc_xive_attach_escalation(vcpu, prio,
>> + xive->single_escalation);
>> if (rc)
>> return rc;
>> }
>> @@ -1214,7 +1216,8 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev,
>> if (xive->qmap & (1 << i)) {
>> r = xive_provision_queue(vcpu, i);
>> if (r == 0 && !xive->single_escalation)
>> - xive_attach_escalation(vcpu, i);
>> + kvmppc_xive_attach_escalation(
>> + vcpu, i, xive->single_escalation);
>> if (r)
>> goto bail;
>> } else {
>> @@ -1229,7 +1232,7 @@ int kvmppc_xive_connect_vcpu(struct kvm_device *dev,
>> }
>>
>> /* If not done above, attach priority 0 escalation */
>> - r = xive_attach_escalation(vcpu, 0);
>> + r = kvmppc_xive_attach_escalation(vcpu, 0, xive->single_escalation);
>> if (r)
>> goto bail;
>>
>> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
>> index b841d339f674..42e824658a30 100644
>> --- a/arch/powerpc/kvm/book3s_xive_native.c
>> +++ b/arch/powerpc/kvm/book3s_xive_native.c
>> @@ -340,6 +340,226 @@ static int kvmppc_xive_native_set_source_config(struct kvmppc_xive *xive,
>> priority, masked, eisn);
>> }
>>
>> +static int xive_native_validate_queue_size(u32 qsize)
>> +{
>> + /*
>> + * We only support 64K pages for the moment. This is also
>> + * advertised in the DT property "ibm,xive-eq-sizes"
>
> IIUC, that won't work properly if you had a guest using 4kiB pages.
> That's fine, but do we have somewhere that checks for that case and
> throws a suitable error?
Not in the device.
So, we should check the current page_size of the guest ? Is there a way
to do that simply from KVM ?
>> + */
>> + switch (qsize) {
>> + case 0: /* EQ reset */
>> + case 16:
>> + return 0;
>> + case 12:
>> + case 21:
>> + case 24:
>> + default:
>> + return -EINVAL;
>> + }
>> +}
>> +
>> +static int kvmppc_xive_native_set_queue_config(struct kvmppc_xive *xive,
>> + long eq_idx, u64 addr)
>> +{
>> + struct kvm *kvm = xive->kvm;
>> + struct kvm_vcpu *vcpu;
>> + struct kvmppc_xive_vcpu *xc;
>> + void __user *ubufp = (u64 __user *) addr;
>
> Nit: that should be (void __user *) on the right, shouldn't it?
yes.
>
>> + u32 server;
>> + u8 priority;
>> + struct kvm_ppc_xive_eq kvm_eq;
>> + int rc;
>> + __be32 *qaddr = 0;
>> + struct page *page;
>> + struct xive_q *q;
>> +
>> + /*
>> + * Demangle priority/server tuple from the EQ identifier
>> + */
>> + priority = (eq_idx & KVM_XIVE_EQ_PRIORITY_MASK) >>
>> + KVM_XIVE_EQ_PRIORITY_SHIFT;
>> + server = (eq_idx & KVM_XIVE_EQ_SERVER_MASK) >>
>> + KVM_XIVE_EQ_SERVER_SHIFT;
>> +
>> + if (copy_from_user(&kvm_eq, ubufp, sizeof(kvm_eq)))
>> + return -EFAULT;
>> +
>> + vcpu = kvmppc_xive_find_server(kvm, server);
>> + if (!vcpu) {
>> + pr_err("Can't find server %d\n", server);
>> + return -ENOENT;
>> + }
>> + xc = vcpu->arch.xive_vcpu;
>> +
>> + if (priority != xive_prio_from_guest(priority)) {
>> + pr_err("Trying to restore invalid queue %d for VCPU %d\n",
>> + priority, server);
>> + return -EINVAL;
>> + }
>> + q = &xc->queues[priority];
>> +
>> + pr_devel("%s VCPU %d priority %d fl:%x sz:%d addr:%llx g:%d idx:%d\n",
>> + __func__, server, priority, kvm_eq.flags,
>> + kvm_eq.qsize, kvm_eq.qpage, kvm_eq.qtoggle, kvm_eq.qindex);
>> +
>> + /*
>> + * We can not tune the EQ configuration from user space. All
>> + * is done in OPAL.
>> + */
>> + if (kvm_eq.flags != 0) {
>> + pr_err("invalid flags %d\n", kvm_eq.flags);
>> + return -EINVAL;
>> + }
>> +
>> + rc = xive_native_validate_queue_size(kvm_eq.qsize);
>> + if (rc) {
>> + pr_err("invalid queue size %d\n", kvm_eq.qsize);
>> + return rc;
>> + }
>> +
>> + /* reset queue and disable queueing */
>> + if (!kvm_eq.qsize) {
>> + q->guest_qpage = 0;
>> + q->guest_qsize = 0;
>> +
>> + rc = xive_native_configure_queue(xc->vp_id, q, priority,
>> + NULL, 0, true);
>> + if (rc) {
>> + pr_err("Failed to reset queue %d for VCPU %d: %d\n",
>> + priority, xc->server_num, rc);
>> + return rc;
>> + }
>> +
>> + if (q->qpage) {
>> + put_page(virt_to_page(q->qpage));
>> + q->qpage = NULL;
>> + }
>> +
>> + return 0;
>> + }
>> +
>> +
>> + page = gfn_to_page(kvm, gpa_to_gfn(kvm_eq.qpage));
>> + if (is_error_page(page)) {
>> + pr_warn("Couldn't get guest page for %llx!\n", kvm_eq.qpage);
>> + return -EINVAL;
>> + }
>
> Yeah.. for the case of a 4kiB page host (these days weird, but not
> actually prohibited, AFAIK) you need to check that the qsize selected
> actually fits within the page.
Ah yes. sure.
>> + qaddr = page_to_virt(page) + (kvm_eq.qpage & ~PAGE_MASK);
>> +
>> + /* Backup queue page guest address for migration */
>
> Hm.. KVM itself shouldn't generally need to know about migration.
> IIUC these values won't change from what qemu set them to be, so it
> should be able to store and migrate them without have to get them back
> from the kernel.
Euh. You are completely right. I don't know why I kept those around.
>> + q->guest_qpage = kvm_eq.qpage;
>> + q->guest_qsize = kvm_eq.qsize;
>> +
>> + rc = xive_native_configure_queue(xc->vp_id, q, priority,
>> + (__be32 *) qaddr, kvm_eq.qsize, true);
>> + if (rc) {
>> + pr_err("Failed to configure queue %d for VCPU %d: %d\n",
>> + priority, xc->server_num, rc);
>> + put_page(page);
>> + return rc;
>> + }
>> +
>> + /*
>> + * Only restore the queue state when needed. When doing the
>> + * H_INT_SET_SOURCE_CONFIG hcall, it should not.
>> + */
>> + if (kvm_eq.qtoggle != 0 || kvm_eq.qindex != 0) {
>> + rc = xive_native_set_queue_state(xc->vp_id, priority,
>> + kvm_eq.qtoggle,
>> + kvm_eq.qindex);
>> + if (rc)
>> + goto error;
>> + }
>> +
>> + rc = kvmppc_xive_attach_escalation(vcpu, priority,
>> + xive->single_escalation);
>> +error:
>> + if (rc)
>> + kvmppc_xive_native_cleanup_queue(vcpu, priority);
>> + return rc;
>> +}
>> +
>> +static int kvmppc_xive_native_get_queue_config(struct kvmppc_xive *xive,
>> + long eq_idx, u64 addr)
>> +{
>> + struct kvm *kvm = xive->kvm;
>> + struct kvm_vcpu *vcpu;
>> + struct kvmppc_xive_vcpu *xc;
>> + struct xive_q *q;
>> + void __user *ubufp = (u64 __user *) addr;
>> + u32 server;
>> + u8 priority;
>> + struct kvm_ppc_xive_eq kvm_eq;
>> + u64 qpage;
>> + u64 qsize;
>> + u64 qeoi_page;
>> + u32 escalate_irq;
>> + u64 qflags;
>> + int rc;
>> +
>> + /*
>> + * Demangle priority/server tuple from the EQ identifier
>> + */
>> + priority = (eq_idx & KVM_XIVE_EQ_PRIORITY_MASK) >>
>> + KVM_XIVE_EQ_PRIORITY_SHIFT;
>> + server = (eq_idx & KVM_XIVE_EQ_SERVER_MASK) >>
>> + KVM_XIVE_EQ_SERVER_SHIFT;
>> +
>> + vcpu = kvmppc_xive_find_server(kvm, server);
>> + if (!vcpu) {
>> + pr_err("Can't find server %d\n", server);
>> + return -ENOENT;
>> + }
>> + xc = vcpu->arch.xive_vcpu;
>> +
>> + if (priority != xive_prio_from_guest(priority)) {
>> + pr_err("invalid priority for queue %d for VCPU %d\n",
>> + priority, server);
>> + return -EINVAL;
>> + }
>> + q = &xc->queues[priority];
>> +
>> + memset(&kvm_eq, 0, sizeof(kvm_eq));
>> +
>> + if (!q->qpage)
>> + return 0;
>> +
>> + rc = xive_native_get_queue_info(xc->vp_id, priority, &qpage, &qsize,
>> + &qeoi_page, &escalate_irq, &qflags);
>> + if (rc)
>> + return rc;
>> +
>> + /*
>> + * Return some information on the EQ configuration in
>> + * OPAL. This is purely informative for now as we can't really
>> + * tune the EQ configuration from user space.
>> + */
>> + kvm_eq.flags = 0;
>> + if (qflags & OPAL_XIVE_EQ_ENABLED)
>> + kvm_eq.flags |= KVM_XIVE_EQ_FLAG_ENABLED;
>> + if (qflags & OPAL_XIVE_EQ_ALWAYS_NOTIFY)
>> + kvm_eq.flags |= KVM_XIVE_EQ_FLAG_ALWAYS_NOTIFY;
>> + if (qflags & OPAL_XIVE_EQ_ESCALATE)
>> + kvm_eq.flags |= KVM_XIVE_EQ_FLAG_ESCALATE;
>
> If there's not really anything it can do about it, does it make sense
> to even expose this info to userspace?
Hmm, good question.
- KVM_XIVE_EQ_FLAG_ENABLED
may be uselessly obvious.
- KVM_XIVE_EQ_FLAG_ALWAYS_NOTIFY
means we do not use the END ESBs to coalesce the events at the END
level. This flag is reflected by the XIVE_EQ_ALWAYS_NOTIFY option
in the sPAPR specs. We don't support the END ESBs but we might one
day.
- KVM_XIVE_EQ_FLAG_ESCALATE
means the EQ is an escalation. QEMU doesn't really care for now
but it's an important information I think.
I tried not to add too many of the END flags, only the relevant ones which
could have an impact in the future modeling.
I think KVM_XIVE_EQ_FLAG_ALWAYS_NOTIFY is important. I was setting it from
QEMU in the hcall but as OPAL does the same blindly I removed it in v3.
>> + kvm_eq.qsize = q->guest_qsize;
>> + kvm_eq.qpage = q->guest_qpage;
>
>> + rc = xive_native_get_queue_state(xc->vp_id, priority, &kvm_eq.qtoggle,
>> + &kvm_eq.qindex);
>> + if (rc)
>> + return rc;
>> +
>> + pr_devel("%s VCPU %d priority %d fl:%x sz:%d addr:%llx g:%d idx:%d\n",
>> + __func__, server, priority, kvm_eq.flags,
>> + kvm_eq.qsize, kvm_eq.qpage, kvm_eq.qtoggle, kvm_eq.qindex);
>> +
>> + if (copy_to_user(ubufp, &kvm_eq, sizeof(kvm_eq)))
>> + return -EFAULT;
>> +
>> + return 0;
>> +}
>> +
>> static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>> struct kvm_device_attr *attr)
>> {
>> @@ -354,6 +574,9 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>> case KVM_DEV_XIVE_GRP_SOURCE_CONFIG:
>> return kvmppc_xive_native_set_source_config(xive, attr->attr,
>> attr->addr);
>> + case KVM_DEV_XIVE_GRP_EQ_CONFIG:
>> + return kvmppc_xive_native_set_queue_config(xive, attr->attr,
>> + attr->addr);
>> }
>> return -ENXIO;
>> }
>> @@ -361,6 +584,13 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>> static int kvmppc_xive_native_get_attr(struct kvm_device *dev,
>> struct kvm_device_attr *attr)
>> {
>> + struct kvmppc_xive *xive = dev->private;
>> +
>> + switch (attr->group) {
>> + case KVM_DEV_XIVE_GRP_EQ_CONFIG:
>> + return kvmppc_xive_native_get_queue_config(xive, attr->attr,
>> + attr->addr);
>> + }
>> return -ENXIO;
>> }
>>
>> @@ -376,6 +606,8 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
>> attr->attr < KVMPPC_XIVE_NR_IRQS)
>> return 0;
>> break;
>> + case KVM_DEV_XIVE_GRP_EQ_CONFIG:
>> + return 0;
>> }
>> return -ENXIO;
>> }
>> diff --git a/Documentation/virtual/kvm/devices/xive.txt b/Documentation/virtual/kvm/devices/xive.txt
>> index 33c64b2cdbe8..a4de64f6e79c 100644
>> --- a/Documentation/virtual/kvm/devices/xive.txt
>> +++ b/Documentation/virtual/kvm/devices/xive.txt
>> @@ -53,3 +53,34 @@ the legacy interrupt mode, referred as XICS (POWER7/8).
>> -ENXIO: CPU event queues not configured or configuration of the
>> underlying HW interrupt failed
>> -EBUSY: No CPU available to serve interrupt
>> +
>> + 4. KVM_DEV_XIVE_GRP_EQ_CONFIG (read-write)
>> + Configures an event queue of a CPU
>> + Attributes:
>> + EQ descriptor identifier (64-bit)
>> + The EQ descriptor identifier is a tuple (server, priority) :
>> + bits: | 63 .... 32 | 31 .. 3 | 2 .. 0
>> + values: | unused | server | priority
>> + The kvm_device_attr.addr points to :
>> + struct kvm_ppc_xive_eq {
>> + __u32 flags;
>> + __u32 qsize;
>> + __u64 qpage;
>> + __u32 qtoggle;
>> + __u32 qindex;
>> + __u8 pad[40];
>> + };
>> + - flags: queue flags
>> + - qsize: queue size (power of 2)
>> + - qpage: real address of queue
>> + - qtoggle: current queue toggle bit
>> + - qindex: current queue index
>> + - pad: reserved for future use
>> + Errors:
>> + -ENOENT: Invalid CPU number
>> + -EINVAL: Invalid priority
>> + -EINVAL: Invalid flags
>> + -EINVAL: Invalid queue size
>> + -EINVAL: Invalid queue address
>> + -EFAULT: Invalid user pointer for attr->addr.
>> + -EIO: Configuration of the underlying HW failed
>
