On 2/25/19 1:35 AM, David Gibson wrote:
> On Fri, Feb 22, 2019 at 12:28:27PM +0100, Cédric Le Goater wrote:
>> The user interface exposes a new capability to let QEMU connect the
>> vCPU to the XIVE KVM device if required. The capability is only
>> advertised on a PowerNV Hypervisor as support for nested guests
>> (pseries KVM Hypervisor) is not yet available.
>>
>> Internally, the interface to the new KVM device is protected with a
>> new interrupt mode: KVMPPC_IRQ_XIVE.
>>
>> Signed-off-by: Cédric Le Goater <clg@xxxxxxxx>
>> ---
>> arch/powerpc/include/asm/kvm_host.h | 1 +
>> arch/powerpc/include/asm/kvm_ppc.h | 13 +++
>> arch/powerpc/kvm/book3s_xive.h | 6 ++
>> include/uapi/linux/kvm.h | 1 +
>> arch/powerpc/kvm/book3s_xive.c | 67 +++++++-----
>> arch/powerpc/kvm/book3s_xive_native.c | 144 ++++++++++++++++++++++++++
>> arch/powerpc/kvm/powerpc.c | 33 ++++++
>> Documentation/virtual/kvm/api.txt | 9 ++
>> 8 files changed, 246 insertions(+), 28 deletions(-)
>>
>> diff --git a/arch/powerpc/include/asm/kvm_host.h b/arch/powerpc/include/asm/kvm_host.h
>> index 9f75a75a07f2..eb8581be0ee8 100644
>> --- a/arch/powerpc/include/asm/kvm_host.h
>> +++ b/arch/powerpc/include/asm/kvm_host.h
>> @@ -448,6 +448,7 @@ struct kvmppc_passthru_irqmap {
>> #define KVMPPC_IRQ_DEFAULT 0
>> #define KVMPPC_IRQ_MPIC 1
>> #define KVMPPC_IRQ_XICS 2 /* Includes a XIVE option */
>> +#define KVMPPC_IRQ_XIVE 3 /* XIVE native exploitation mode */
>>
>> #define MMIO_HPTE_CACHE_SIZE 4
>>
>> diff --git a/arch/powerpc/include/asm/kvm_ppc.h b/arch/powerpc/include/asm/kvm_ppc.h
>> index 4b72ddde7dc1..1e61877fe147 100644
>> --- a/arch/powerpc/include/asm/kvm_ppc.h
>> +++ b/arch/powerpc/include/asm/kvm_ppc.h
>> @@ -594,6 +594,14 @@ extern int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 irq,
>> int level, bool line_status);
>> extern void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu);
>>
>> +static inline int kvmppc_xive_enabled(struct kvm_vcpu *vcpu)
>> +{
>> + return vcpu->arch.irq_type == KVMPPC_IRQ_XIVE;
>> +}
>> +
>> +extern int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev,
>> + struct kvm_vcpu *vcpu, u32 cpu);
>> +extern void kvmppc_xive_native_cleanup_vcpu(struct kvm_vcpu *vcpu);
>> extern void kvmppc_xive_native_init_module(void);
>> extern void kvmppc_xive_native_exit_module(void);
>>
>> @@ -621,6 +629,11 @@ static inline int kvmppc_xive_set_irq(struct kvm *kvm, int irq_source_id, u32 ir
>> int level, bool line_status) { return -ENODEV; }
>> static inline void kvmppc_xive_push_vcpu(struct kvm_vcpu *vcpu) { }
>>
>> +static inline int kvmppc_xive_enabled(struct kvm_vcpu *vcpu)
>> + { return 0; }
>> +static inline int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev,
>> + struct kvm_vcpu *vcpu, u32 cpu) { return -EBUSY; }
>> +static inline void kvmppc_xive_native_cleanup_vcpu(struct kvm_vcpu *vcpu) { }
>> static inline void kvmppc_xive_native_init_module(void) { }
>> static inline void kvmppc_xive_native_exit_module(void) { }
>>
>> diff --git a/arch/powerpc/kvm/book3s_xive.h b/arch/powerpc/kvm/book3s_xive.h
>> index a08ae6fd4c51..bcb1bbcf0359 100644
>> --- a/arch/powerpc/kvm/book3s_xive.h
>> +++ b/arch/powerpc/kvm/book3s_xive.h
>> @@ -248,5 +248,11 @@ extern int (*__xive_vm_h_ipi)(struct kvm_vcpu *vcpu, unsigned long server,
>> extern int (*__xive_vm_h_cppr)(struct kvm_vcpu *vcpu, unsigned long cppr);
>> extern int (*__xive_vm_h_eoi)(struct kvm_vcpu *vcpu, unsigned long xirr);
>>
>> +/*
>> + * Common Xive routines for XICS-over-XIVE and XIVE native
>> + */
>> +void kvmppc_xive_disable_vcpu_interrupts(struct kvm_vcpu *vcpu);
>> +int kvmppc_xive_debug_show_queues(struct seq_file *m, struct kvm_vcpu *vcpu);
>> +
>> #endif /* CONFIG_KVM_XICS */
>> #endif /* _KVM_PPC_BOOK3S_XICS_H */
>> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
>> index e6368163d3a0..52bf74a1616e 100644
>> --- a/include/uapi/linux/kvm.h
>> +++ b/include/uapi/linux/kvm.h
>> @@ -988,6 +988,7 @@ struct kvm_ppc_resize_hpt {
>> #define KVM_CAP_ARM_VM_IPA_SIZE 165
>> #define KVM_CAP_MANUAL_DIRTY_LOG_PROTECT 166
>> #define KVM_CAP_HYPERV_CPUID 167
>> +#define KVM_CAP_PPC_IRQ_XIVE 168
>>
>> #ifdef KVM_CAP_IRQ_ROUTING
>>
>> diff --git a/arch/powerpc/kvm/book3s_xive.c b/arch/powerpc/kvm/book3s_xive.c
>> index f78d002f0fe0..d1cc18a5b1c4 100644
>> --- a/arch/powerpc/kvm/book3s_xive.c
>> +++ b/arch/powerpc/kvm/book3s_xive.c
>> @@ -1049,7 +1049,7 @@ int kvmppc_xive_clr_mapped(struct kvm *kvm, unsigned long guest_irq,
>> }
>> EXPORT_SYMBOL_GPL(kvmppc_xive_clr_mapped);
>>
>> -static void kvmppc_xive_disable_vcpu_interrupts(struct kvm_vcpu *vcpu)
>> +void kvmppc_xive_disable_vcpu_interrupts(struct kvm_vcpu *vcpu)
>> {
>> struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> struct kvm *kvm = vcpu->kvm;
>> @@ -1883,6 +1883,43 @@ static int kvmppc_xive_create(struct kvm_device *dev, u32 type)
>> return 0;
>> }
>>
>> +int kvmppc_xive_debug_show_queues(struct seq_file *m, struct kvm_vcpu *vcpu)
>> +{
>> + struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> + unsigned int i;
>> +
>> + for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {
>> + struct xive_q *q = &xc->queues[i];
>> + u32 i0, i1, idx;
>> +
>> + if (!q->qpage && !xc->esc_virq[i])
>> + continue;
>> +
>> + seq_printf(m, " [q%d]: ", i);
>> +
>> + if (q->qpage) {
>> + idx = q->idx;
>> + i0 = be32_to_cpup(q->qpage + idx);
>> + idx = (idx + 1) & q->msk;
>> + i1 = be32_to_cpup(q->qpage + idx);
>> + seq_printf(m, "T=%d %08x %08x...\n", q->toggle,
>> + i0, i1);
>> + }
>> + if (xc->esc_virq[i]) {
>> + struct irq_data *d = irq_get_irq_data(xc->esc_virq[i]);
>> + struct xive_irq_data *xd =
>> + irq_data_get_irq_handler_data(d);
>> + u64 pq = xive_vm_esb_load(xd, XIVE_ESB_GET);
>> +
>> + seq_printf(m, "E:%c%c I(%d:%llx:%llx)",
>> + (pq & XIVE_ESB_VAL_P) ? 'P' : 'p',
>> + (pq & XIVE_ESB_VAL_Q) ? 'Q' : 'q',
>> + xc->esc_virq[i], pq, xd->eoi_page);
>> + seq_puts(m, "\n");
>> + }
>> + }
>> + return 0;
>> +}
>>
>> static int xive_debug_show(struct seq_file *m, void *private)
>> {
>> @@ -1908,7 +1945,6 @@ static int xive_debug_show(struct seq_file *m, void *private)
>>
>> kvm_for_each_vcpu(i, vcpu, kvm) {
>> struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> - unsigned int i;
>>
>> if (!xc)
>> continue;
>> @@ -1918,33 +1954,8 @@ static int xive_debug_show(struct seq_file *m, void *private)
>> xc->server_num, xc->cppr, xc->hw_cppr,
>> xc->mfrr, xc->pending,
>> xc->stat_rm_h_xirr, xc->stat_vm_h_xirr);
>> - for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {
>> - struct xive_q *q = &xc->queues[i];
>> - u32 i0, i1, idx;
>>
>> - if (!q->qpage && !xc->esc_virq[i])
>> - continue;
>> -
>> - seq_printf(m, " [q%d]: ", i);
>> -
>> - if (q->qpage) {
>> - idx = q->idx;
>> - i0 = be32_to_cpup(q->qpage + idx);
>> - idx = (idx + 1) & q->msk;
>> - i1 = be32_to_cpup(q->qpage + idx);
>> - seq_printf(m, "T=%d %08x %08x... \n", q->toggle, i0, i1);
>> - }
>> - if (xc->esc_virq[i]) {
>> - struct irq_data *d = irq_get_irq_data(xc->esc_virq[i]);
>> - struct xive_irq_data *xd = irq_data_get_irq_handler_data(d);
>> - u64 pq = xive_vm_esb_load(xd, XIVE_ESB_GET);
>> - seq_printf(m, "E:%c%c I(%d:%llx:%llx)",
>> - (pq & XIVE_ESB_VAL_P) ? 'P' : 'p',
>> - (pq & XIVE_ESB_VAL_Q) ? 'Q' : 'q',
>> - xc->esc_virq[i], pq, xd->eoi_page);
>> - seq_printf(m, "\n");
>> - }
>> - }
>> + kvmppc_xive_debug_show_queues(m, vcpu);
>>
>> t_rm_h_xirr += xc->stat_rm_h_xirr;
>> t_rm_h_ipoll += xc->stat_rm_h_ipoll;
>> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
>> index e475ce83ad14..1f3da47a4a6a 100644
>> --- a/arch/powerpc/kvm/book3s_xive_native.c
>> +++ b/arch/powerpc/kvm/book3s_xive_native.c
>> @@ -31,6 +31,128 @@
>>
>> #include "book3s_xive.h"
>>
>> +static void kvmppc_xive_native_cleanup_queue(struct kvm_vcpu *vcpu, int prio)
>> +{
>> + struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> + struct xive_q *q = &xc->queues[prio];
>> +
>> + xive_native_disable_queue(xc->vp_id, q, prio);
>> + if (q->qpage) {
>> + put_page(virt_to_page(q->qpage));
>> + q->qpage = NULL;
>> + }
>> +}
>> +
>> +void kvmppc_xive_native_cleanup_vcpu(struct kvm_vcpu *vcpu)
>> +{
>> + struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> + int i;
>> +
>> + if (!kvmppc_xive_enabled(vcpu))
>> + return;
>> +
>> + if (!xc)
>> + return;
>> +
>> + pr_devel("native_cleanup_vcpu(cpu=%d)\n", xc->server_num);
>> +
>> + /* Ensure no interrupt is still routed to that VP */
>> + xc->valid = false;
>> + kvmppc_xive_disable_vcpu_interrupts(vcpu);
>> +
>> + /* Disable the VP */
>> + xive_native_disable_vp(xc->vp_id);
>> +
>> + /* Free the queues & associated interrupts */
>> + for (i = 0; i < KVMPPC_XIVE_Q_COUNT; i++) {
>> + /* Free the escalation irq */
>> + if (xc->esc_virq[i]) {
>> + free_irq(xc->esc_virq[i], vcpu);
>> + irq_dispose_mapping(xc->esc_virq[i]);
>> + kfree(xc->esc_virq_names[i]);
>> + xc->esc_virq[i] = 0;
>> + }
>> +
>> + /* Free the queue */
>> + kvmppc_xive_native_cleanup_queue(vcpu, i);
>> + }
>> +
>> + /* Free the VP */
>> + kfree(xc);
>> +
>> + /* Cleanup the vcpu */
>> + vcpu->arch.irq_type = KVMPPC_IRQ_DEFAULT;
>> + vcpu->arch.xive_vcpu = NULL;
>> +}
>> +
>> +int kvmppc_xive_native_connect_vcpu(struct kvm_device *dev,
>> + struct kvm_vcpu *vcpu, u32 cpu)
>> +{
>> + struct kvmppc_xive *xive = dev->private;
>> + struct kvmppc_xive_vcpu *xc;
>> + int rc;
>> +
>> + pr_devel("native_connect_vcpu(cpu=%d)\n", cpu);
>> +
>> + if (dev->ops != &kvm_xive_native_ops) {
>> + pr_devel("Wrong ops !\n");
>> + return -EPERM;
>> + }
>> + if (xive->kvm != vcpu->kvm)
>> + return -EPERM;
>> + if (vcpu->arch.irq_type != KVMPPC_IRQ_DEFAULT)
>> + return -EBUSY;
>> + if (kvmppc_xive_find_server(vcpu->kvm, cpu)) {
>
> You haven't taken the kvm->lock yet, so couldn't a race mean a
> duplicate server gets inserted after you make this check?
>
>> + pr_devel("Duplicate !\n");
>> + return -EEXIST;
>> + }
>> + if (cpu >= KVM_MAX_VCPUS) {
>> + pr_devel("Out of bounds !\n");
>> + return -EINVAL;
>> + }
>> + xc = kzalloc(sizeof(*xc), GFP_KERNEL);
>> + if (!xc)
>> + return -ENOMEM;
>> +
>> + mutex_lock(&vcpu->kvm->lock);
>> + vcpu->arch.xive_vcpu = xc;
>
> Similarly you don't verify this is NULL after taking the lock, so
> couldn't another thread race and make a connect which gets clobbered
> here?
Yes. this is not very safe ... We need to clean up all the KVM device
methods doing the connection of the presenter to the vCPU AFAICT.
I will fix the XIVE native one for now.
And also, this CPU parameter is useless. There is no reason to connect
a vCPU from another vCPU.
>> + xc->xive = xive;
>> + xc->vcpu = vcpu;
>> + xc->server_num = cpu;
>> + xc->vp_id = xive->vp_base + cpu;
>
> Hrm. This ties the internal VP id to the userspace chosen server
> number, which isn't ideal. It puts a constraint on those server
> numbers that you wouldn't otherwise have.
Ah yes. I should be using the kvmppc_pack_vcpu_id() like we do for
the XICS-over-XIVE device probably. I need to check that it is correct
in this mode.
Thanks,
C.
>> + xc->valid = true;
>> +
>> + rc = xive_native_get_vp_info(xc->vp_id, &xc->vp_cam, &xc->vp_chip_id);
>> + if (rc) {
>> + pr_err("Failed to get VP info from OPAL: %d\n", rc);
>> + goto bail;
>> + }
>> +
>> + /*
>> + * Enable the VP first as the single escalation mode will
>> + * affect escalation interrupts numbering
>> + */
>> + rc = xive_native_enable_vp(xc->vp_id, xive->single_escalation);
>> + if (rc) {
>> + pr_err("Failed to enable VP in OPAL: %d\n", rc);
>> + goto bail;
>> + }
>> +
>> + /* Configure VCPU fields for use by assembly push/pull */
>> + vcpu->arch.xive_saved_state.w01 = cpu_to_be64(0xff000000);
>> + vcpu->arch.xive_cam_word = cpu_to_be32(xc->vp_cam | TM_QW1W2_VO);
>> +
>> + /* TODO: initialize queues ? */
>> +
>> +bail:
>> + vcpu->arch.irq_type = KVMPPC_IRQ_XIVE;
>> + mutex_unlock(&vcpu->kvm->lock);
>> + if (rc)
>> + kvmppc_xive_native_cleanup_vcpu(vcpu);
>> +
>> + return rc;
>> +}
>> +
>> static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>> struct kvm_device_attr *attr)
>> {
>> @@ -126,10 +248,32 @@ static int xive_native_debug_show(struct seq_file *m, void *private)
>> {
>> struct kvmppc_xive *xive = m->private;
>> struct kvm *kvm = xive->kvm;
>> + struct kvm_vcpu *vcpu;
>> + unsigned int i;
>>
>> if (!kvm)
>> return 0;
>>
>> + seq_puts(m, "=========\nVCPU state\n=========\n");
>> +
>> + kvm_for_each_vcpu(i, vcpu, kvm) {
>> + struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> +
>> + if (!xc)
>> + continue;
>> +
>> + seq_printf(m, "cpu server %#x NSR=%02x CPPR=%02x IBP=%02x PIPR=%02x w01=%016llx w2=%08x\n",
>> + xc->server_num,
>> + vcpu->arch.xive_saved_state.nsr,
>> + vcpu->arch.xive_saved_state.cppr,
>> + vcpu->arch.xive_saved_state.ipb,
>> + vcpu->arch.xive_saved_state.pipr,
>> + vcpu->arch.xive_saved_state.w01,
>> + (u32) vcpu->arch.xive_cam_word);
>> +
>> + kvmppc_xive_debug_show_queues(m, vcpu);
>> + }
>> +
>> return 0;
>> }
>>
>> diff --git a/arch/powerpc/kvm/powerpc.c b/arch/powerpc/kvm/powerpc.c
>> index 8c69af10f91d..a38a643a24dd 100644
>> --- a/arch/powerpc/kvm/powerpc.c
>> +++ b/arch/powerpc/kvm/powerpc.c
>> @@ -570,6 +570,12 @@ int kvm_vm_ioctl_check_extension(struct kvm *kvm, long ext)
>> case KVM_CAP_PPC_GET_CPU_CHAR:
>> r = 1;
>> break;
>> +#ifdef CONFIG_KVM_XIVE
>> + case KVM_CAP_PPC_IRQ_XIVE:
>> + /* only for PowerNV */
>> + r = !!cpu_has_feature(CPU_FTR_HVMODE);
>> + break;
>> +#endif
>>
>> case KVM_CAP_PPC_ALLOC_HTAB:
>> r = hv_enabled;
>> @@ -753,6 +759,9 @@ void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)
>> else
>> kvmppc_xics_free_icp(vcpu);
>> break;
>> + case KVMPPC_IRQ_XIVE:
>> + kvmppc_xive_native_cleanup_vcpu(vcpu);
>> + break;
>> }
>>
>> kvmppc_core_vcpu_free(vcpu);
>> @@ -1941,6 +1950,30 @@ static int kvm_vcpu_ioctl_enable_cap(struct kvm_vcpu *vcpu,
>> break;
>> }
>> #endif /* CONFIG_KVM_XICS */
>> +#ifdef CONFIG_KVM_XIVE
>> + case KVM_CAP_PPC_IRQ_XIVE: {
>> + struct fd f;
>> + struct kvm_device *dev;
>> +
>> + r = -EBADF;
>> + f = fdget(cap->args[0]);
>> + if (!f.file)
>> + break;
>> +
>> + r = -ENXIO;
>> + if (!xive_enabled())
>> + break;
>> +
>> + r = -EPERM;
>> + dev = kvm_device_from_filp(f.file);
>> + if (dev)
>> + r = kvmppc_xive_native_connect_vcpu(dev, vcpu,
>> + cap->args[1]);
>> +
>> + fdput(f);
>> + break;
>> + }
>> +#endif /* CONFIG_KVM_XIVE */
>> #ifdef CONFIG_KVM_BOOK3S_HV_POSSIBLE
>> case KVM_CAP_PPC_FWNMI:
>> r = -EINVAL;
>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>> index 356156f5c52d..1db1435769b4 100644
>> --- a/Documentation/virtual/kvm/api.txt
>> +++ b/Documentation/virtual/kvm/api.txt
>> @@ -4458,6 +4458,15 @@ struct kvm_sync_regs {
>> struct kvm_vcpu_events events;
>> };
>>
>> +6.75 KVM_CAP_PPC_IRQ_XIVE
>> +
>> +Architectures: ppc
>> +Target: vcpu
>> +Parameters: args[0] is the XIVE device fd
>> + args[1] is the XIVE CPU number (server ID) for this vcpu
>> +
>> +This capability connects the vcpu to an in-kernel XIVE device.
>> +
>> 7. Capabilities that can be enabled on VMs
>> ------------------------------------------
>>
>
