[PATCH 09/19] KVM: PPC: Book3S HV: add a SET_SOURCE control to the XIVE native device
Cédric Le Goater
clg at kaod.org
Tue Feb 5 06:07:20 AEDT 2019
On 2/4/19 5:57 AM, David Gibson wrote:
> On Mon, Jan 07, 2019 at 07:43:21PM +0100, Cédric Le Goater wrote:
>> Interrupt sources are simply created at the OPAL level and then
>> MASKED. KVM only needs to know about their type: LSI or MSI.
>
> This commit message isn't very illuminating.
There is room for improvement certainly.
>>
>> Signed-off-by: Cédric Le Goater <clg at kaod.org>
>> ---
>> arch/powerpc/include/uapi/asm/kvm.h | 5 +
>> arch/powerpc/kvm/book3s_xive_native.c | 98 +++++++++++++++++++
>> .../powerpc/kvm/book3s_xive_native_template.c | 27 +++++
>> 3 files changed, 130 insertions(+)
>> create mode 100644 arch/powerpc/kvm/book3s_xive_native_template.c
>>
>> diff --git a/arch/powerpc/include/uapi/asm/kvm.h b/arch/powerpc/include/uapi/asm/kvm.h
>> index 8b78b12aa118..6fc9660c5aec 100644
>> --- a/arch/powerpc/include/uapi/asm/kvm.h
>> +++ b/arch/powerpc/include/uapi/asm/kvm.h
>> @@ -680,5 +680,10 @@ struct kvm_ppc_cpu_char {
>> #define KVM_DEV_XIVE_GET_ESB_FD 1
>> #define KVM_DEV_XIVE_GET_TIMA_FD 2
>> #define KVM_DEV_XIVE_VC_BASE 3
>> +#define KVM_DEV_XIVE_GRP_SOURCES 2 /* 64-bit source attributes */
>> +
>> +/* Layout of 64-bit XIVE source attribute values */
>> +#define KVM_XIVE_LEVEL_SENSITIVE (1ULL << 0)
>> +#define KVM_XIVE_LEVEL_ASSERTED (1ULL << 1)
>>
>> #endif /* __LINUX_KVM_POWERPC_H */
>> diff --git a/arch/powerpc/kvm/book3s_xive_native.c b/arch/powerpc/kvm/book3s_xive_native.c
>> index 29a62914de55..2518640d4a58 100644
>> --- a/arch/powerpc/kvm/book3s_xive_native.c
>> +++ b/arch/powerpc/kvm/book3s_xive_native.c
>> @@ -31,6 +31,24 @@
>>
>> #include "book3s_xive.h"
>>
>> +/*
>> + * We still instantiate them here because we use some of the
>> + * generated utility functions as well in this file.
>
> And this comment is downright cryptic.
I have removed this part now that the hcalls are not done under
real mode anymore.
>
>> + */
>> +#define XIVE_RUNTIME_CHECKS
>> +#define X_PFX xive_vm_
>> +#define X_STATIC static
>> +#define X_STAT_PFX stat_vm_
>> +#define __x_tima xive_tima
>> +#define __x_eoi_page(xd) ((void __iomem *)((xd)->eoi_mmio))
>> +#define __x_trig_page(xd) ((void __iomem *)((xd)->trig_mmio))
>> +#define __x_writeb __raw_writeb
>> +#define __x_readw __raw_readw
>> +#define __x_readq __raw_readq
>> +#define __x_writeq __raw_writeq
>> +
>> +#include "book3s_xive_native_template.c"
>> +
>> static void xive_native_cleanup_queue(struct kvm_vcpu *vcpu, int prio)
>> {
>> struct kvmppc_xive_vcpu *xc = vcpu->arch.xive_vcpu;
>> @@ -305,6 +323,78 @@ static int kvmppc_xive_native_get_tima_fd(struct kvmppc_xive *xive, u64 addr)
>> return put_user(ret, ubufp);
>> }
>>
>> +static int kvmppc_xive_native_set_source(struct kvmppc_xive *xive, long irq,
>> + u64 addr)
>> +{
>> + struct kvmppc_xive_src_block *sb;
>> + struct kvmppc_xive_irq_state *state;
>> + u64 __user *ubufp = (u64 __user *) addr;
>> + u64 val;
>> + u16 idx;
>> +
>> + pr_devel("%s irq=0x%lx\n", __func__, irq);
>> +
>> + if (irq < KVMPPC_XIVE_FIRST_IRQ || irq >= KVMPPC_XIVE_NR_IRQS)
>> + return -ENOENT;
>> +
>> + sb = kvmppc_xive_find_source(xive, irq, &idx);
>> + if (!sb) {
>> + pr_debug("No source, creating source block...\n");
>
> Doesn't this need to be protected by some lock?
>
>> + sb = kvmppc_xive_create_src_block(xive, irq);
>> + if (!sb) {
>> + pr_err("Failed to create block...\n");
>> + return -ENOMEM;
>> + }
>> + }
>> + state = &sb->irq_state[idx];
>> +
>> + if (get_user(val, ubufp)) {
>> + pr_err("fault getting user info !\n");
>> + return -EFAULT;
>> + }
>> +
>> + /*
>> + * If the source doesn't already have an IPI, allocate
>> + * one and get the corresponding data
>> + */
>> + if (!state->ipi_number) {
>> + state->ipi_number = xive_native_alloc_irq();
>> + if (state->ipi_number == 0) {
>> + pr_err("Failed to allocate IRQ !\n");
>> + return -ENOMEM;
>> + }
>
> Am I right in thinking this is the point at which a specific guest irq
> number gets bound to a specific host irq number?
yes. the XIVE IRQ state caches this information and 'state' should be
protected before being assigned, indeed ... The XICS-over-XIVE device
also has the same race issue.
It's not showing because where initializing the KVM device sequentially
from QEMU and only once.
Thanks,
C.
>
>> + xive_native_populate_irq_data(state->ipi_number,
>> + &state->ipi_data);
>> + pr_debug("%s allocated hw_irq=0x%x for irq=0x%lx\n", __func__,
>> + state->ipi_number, irq);
>> + }
>> +
>> + arch_spin_lock(&sb->lock);
>> +
>> + /* Restore LSI state */
>> + if (val & KVM_XIVE_LEVEL_SENSITIVE) {
>> + state->lsi = true;
>> + if (val & KVM_XIVE_LEVEL_ASSERTED)
>> + state->asserted = true;
>> + pr_devel(" LSI ! Asserted=%d\n", state->asserted);
>> + }
>> +
>> + /* Mask IRQ to start with */
>> + state->act_server = 0;
>> + state->act_priority = MASKED;
>> + xive_vm_esb_load(&state->ipi_data, XIVE_ESB_SET_PQ_01);
>> + xive_native_configure_irq(state->ipi_number, 0, MASKED, 0);
>> +
>> + /* Increment the number of valid sources and mark this one valid */
>> + if (!state->valid)
>> + xive->src_count++;
>> + state->valid = true;
>> +
>> + arch_spin_unlock(&sb->lock);
>> +
>> + return 0;
>> +}
>> +
>> static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>> struct kvm_device_attr *attr)
>> {
>> @@ -317,6 +407,9 @@ static int kvmppc_xive_native_set_attr(struct kvm_device *dev,
>> return kvmppc_xive_native_set_vc_base(xive, attr->addr);
>> }
>> break;
>> + case KVM_DEV_XIVE_GRP_SOURCES:
>> + return kvmppc_xive_native_set_source(xive, attr->attr,
>> + attr->addr);
>> }
>> return -ENXIO;
>> }
>> @@ -353,6 +446,11 @@ static int kvmppc_xive_native_has_attr(struct kvm_device *dev,
>> return 0;
>> }
>> break;
>> + case KVM_DEV_XIVE_GRP_SOURCES:
>> + if (attr->attr >= KVMPPC_XIVE_FIRST_IRQ &&
>> + attr->attr < KVMPPC_XIVE_NR_IRQS)
>> + return 0;
>> + break;
>> }
>> return -ENXIO;
>> }
>> diff --git a/arch/powerpc/kvm/book3s_xive_native_template.c b/arch/powerpc/kvm/book3s_xive_native_template.c
>> new file mode 100644
>> index 000000000000..e7260da4a596
>> --- /dev/null
>> +++ b/arch/powerpc/kvm/book3s_xive_native_template.c
>> @@ -0,0 +1,27 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright (c) 2017-2019, IBM Corporation.
>> + */
>> +
>> +/* File to be included by other .c files */
>> +
>> +#define XGLUE(a, b) a##b
>> +#define GLUE(a, b) XGLUE(a, b)
>> +
>> +/*
>> + * TODO: introduce a common template file with the XIVE native layer
>> + * and the XICS-on-XIVE glue for the utility functions
>> + */
>> +static u8 GLUE(X_PFX, esb_load)(struct xive_irq_data *xd, u32 offset)
>> +{
>> + u64 val;
>> +
>> + if (xd->flags & XIVE_IRQ_FLAG_SHIFT_BUG)
>> + offset |= offset << 4;
>> +
>> + val = __x_readq(__x_eoi_page(xd) + offset);
>> +#ifdef __LITTLE_ENDIAN__
>> + val >>= 64-8;
>> +#endif
>> + return (u8)val;
>> +}
>
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