[PATCH v2 06/16] KVM: PPC: Book3S HV: XIVE: add controls for the EQ configuration
David Gibson
david at gibson.dropbear.id.au
Mon Feb 25 13:39:55 AEDT 2019
On Fri, Feb 22, 2019 at 12:28:30PM +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. They will also be used to
> restore the configuration of the XIVE EQs in the KVM device and to
> capture the internal runtime state of the EQs. Both 'get' and 'set'
> rely on an OPAL call to access from the XIVE interrupt controller the
> EQ toggle bit and EQ index which are updated by the HW 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 at kaod.org>
> ---
> 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 | 207 +++++++++++++++++++++
> Documentation/virtual/kvm/devices/xive.txt | 29 +++
> 6 files changed, 270 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 91899c7f9abd..177e43f3edaf 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 attributes */
> #define KVM_DEV_XIVE_GRP_SOURCE_CONFIG 3 /* 64-bit source attributes */
> +#define KVM_DEV_XIVE_GRP_EQ_CONFIG 4 /* 64-bit eq attributes */
>
> /* 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 attribute */
> +#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 64-bit eq attribute values */
> +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 ab3ac152980d..6660d138c6b7 100644
> --- a/arch/powerpc/kvm/book3s_xive.h
> +++ b/arch/powerpc/kvm/book3s_xive.h
> @@ -267,6 +267,8 @@ 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 086da91d7c6e..7431e31bc541 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;
> }
> @@ -1219,7 +1221,8 @@ 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 {
> @@ -1234,7 +1237,7 @@ 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 cb5a5c6e05af..34a35bcf550c 100644
> --- a/arch/powerpc/kvm/book3s_xive_native.c
> +++ b/arch/powerpc/kvm/book3s_xive_native.c
> @@ -341,6 +341,201 @@ static int kvmppc_xive_native_set_source_config(struct kvmppc_xive *xive,
> priority, eisn);
> }
>
> +static int xive_native_validate_queue_size(u32 qsize)
> +{
> + switch (qsize) {
> + case 12:
> + case 16:
> + case 21:
> + case 24:
> + case 0:
> + return 0;
> + 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;
> + 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 index
> + */
> + 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];
You need to validate the 'flags' field (AFAICT we don't actually have
any flags yet, so it's only valid it if is 0.
> +
> + 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);
> +
> + 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 -ENOMEM;
Nit: I don't think ENOMEM is the right error here. ENOMEM indicates
that the kernel couldn't allocate enough memory to complete whatever
you asked. Here the problem is the user supplied a bad guest address,
which is a rather different error. EFAULT is closer, but still not
quite right, since it could be a valid user address but not a valid
guest address. There are probably existing KVM calls that could hit
this problem, I wonder what they use.
> + }
> + qaddr = page_to_virt(page) + (kvm_eq.qpage & ~PAGE_MASK);
> +
> + /* Backup queue page guest address for migration */
> + 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;
> + }
> +
> + 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 index
> + */
> + 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;
> +
> + 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;
> +
> + 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)
> {
> @@ -355,6 +550,9 @@ 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;
> }
> @@ -362,6 +560,13 @@ 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;
> }
>
> @@ -377,6 +582,8 @@ 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 4f513a1880c7..c0b5d9bd43fb 100644
> --- a/Documentation/virtual/kvm/devices/xive.txt
> +++ b/Documentation/virtual/kvm/devices/xive.txt
> @@ -52,3 +52,32 @@ 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 or invalid queue size
> + -EFAULT: Invalid user pointer for attr->addr.
> + -ENOMEM: Invalid queue address
> + -EIO: Configuration of the underlying HW failed
--
David Gibson | I'll have my music baroque, and my code
david AT gibson.dropbear.id.au | minimalist, thank you. NOT _the_ _other_
| _way_ _around_!
http://www.ozlabs.org/~dgibson
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