On Wed, Apr 17, 2024 at 11:34:45AM -0400,
Paolo Bonzini <pbonzini@xxxxxxxxxx> wrote:
> From: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
>
> Add a new ioctl KVM_MAP_MEMORY in the KVM common code. It iterates on the
> memory range and calls the arch-specific function. Add stub arch function
> as a weak symbol.
>
> Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
> Signed-off-by: Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
> Reviewed-by: Rick Edgecombe <rick.p.edgecombe@xxxxxxxxx>
> Message-ID: <819322b8f25971f2b9933bfa4506e618508ad782.1712785629.git.isaku.yamahata@xxxxxxxxx>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> include/linux/kvm_host.h | 5 ++++
> include/uapi/linux/kvm.h | 10 +++++++
> virt/kvm/Kconfig | 3 ++
> virt/kvm/kvm_main.c | 61 ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 79 insertions(+)
>
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 8dea11701ab2..2b0f0240a64c 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -2478,4 +2478,9 @@ long kvm_gmem_populate(struct kvm *kvm, gfn_t gfn, void __user *src, long npages
> void kvm_arch_gmem_invalidate(kvm_pfn_t start, kvm_pfn_t end);
> #endif
>
> +#ifdef CONFIG_KVM_GENERIC_MAP_MEMORY
> +int kvm_arch_vcpu_map_memory(struct kvm_vcpu *vcpu,
> + struct kvm_map_memory *mapping);
> +#endif
> +
> #endif
> diff --git a/include/uapi/linux/kvm.h b/include/uapi/linux/kvm.h
> index 2190adbe3002..4d233f44c613 100644
> --- a/include/uapi/linux/kvm.h
> +++ b/include/uapi/linux/kvm.h
> @@ -917,6 +917,7 @@ struct kvm_enable_cap {
> #define KVM_CAP_MEMORY_ATTRIBUTES 233
> #define KVM_CAP_GUEST_MEMFD 234
> #define KVM_CAP_VM_TYPES 235
> +#define KVM_CAP_MAP_MEMORY 236
>
> struct kvm_irq_routing_irqchip {
> __u32 irqchip;
> @@ -1548,4 +1549,13 @@ struct kvm_create_guest_memfd {
> __u64 reserved[6];
> };
>
> +#define KVM_MAP_MEMORY _IOWR(KVMIO, 0xd5, struct kvm_map_memory)
> +
> +struct kvm_map_memory {
> + __u64 base_address;
> + __u64 size;
> + __u64 flags;
> + __u64 padding[5];
> +};
> +
> #endif /* __LINUX_KVM_H */
> diff --git a/virt/kvm/Kconfig b/virt/kvm/Kconfig
> index 754c6c923427..1b94126622e8 100644
> --- a/virt/kvm/Kconfig
> +++ b/virt/kvm/Kconfig
> @@ -67,6 +67,9 @@ config HAVE_KVM_INVALID_WAKEUPS
> config KVM_GENERIC_DIRTYLOG_READ_PROTECT
> bool
>
> +config KVM_GENERIC_MAP_MEMORY
> + bool
> +
> config KVM_COMPAT
> def_bool y
> depends on KVM && COMPAT && !(S390 || ARM64 || RISCV)
> diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c
> index 38b498669ef9..350ead98e9a6 100644
> --- a/virt/kvm/kvm_main.c
> +++ b/virt/kvm/kvm_main.c
> @@ -4379,6 +4379,47 @@ static int kvm_vcpu_ioctl_get_stats_fd(struct kvm_vcpu *vcpu)
> return fd;
> }
>
> +#ifdef CONFIG_KVM_GENERIC_MAP_MEMORY
> +static int kvm_vcpu_map_memory(struct kvm_vcpu *vcpu,
> + struct kvm_map_memory *mapping)
> +{
> + int idx, r;
> + u64 full_size;
> +
> + if (mapping->flags)
> + return -EINVAL;
> +
> + if (!PAGE_ALIGNED(mapping->base_address) ||
> + !PAGE_ALIGNED(mapping->size) ||
> + mapping->base_address + mapping->size <= mapping->base_address)
> + return -EINVAL;
> +
> + vcpu_load(vcpu);
> + idx = srcu_read_lock(&vcpu->kvm->srcu);
> +
> + r = 0;
> + full_size = mapping->size;
> + while (mapping->size) {
> + if (signal_pending(current)) {
> + r = -EINTR;
> + break;
> + }
> +
> + r = kvm_arch_vcpu_map_memory(vcpu, mapping);
> + if (r)
> + break;
> +
> + cond_resched();
> + }
> +
> + srcu_read_unlock(&vcpu->kvm->srcu, idx);
> + vcpu_put(vcpu);
> +
> + /* Return success if at least one page was mapped successfully. */
> + return full_size == mapping->size ? r : 0;
> +}
> +#endif
> +
> static long kvm_vcpu_ioctl(struct file *filp,
> unsigned int ioctl, unsigned long arg)
> {
> @@ -4580,6 +4621,20 @@ static long kvm_vcpu_ioctl(struct file *filp,
> r = kvm_vcpu_ioctl_get_stats_fd(vcpu);
> break;
> }
> +#ifdef CONFIG_KVM_GENERIC_MAP_MEMORY
> + case KVM_MAP_MEMORY: {
> + struct kvm_map_memory mapping;
> +
> + r = -EFAULT;
> + if (copy_from_user(&mapping, argp, sizeof(mapping)))
> + break;
> + r = kvm_vcpu_map_memory(vcpu, &mapping);
> + /* Pass back leftover range. */
> + if (copy_to_user(argp, &mapping, sizeof(mapping)))
> + r = -EFAULT;
> + break;
> + }
> +#endif
> default:
> r = kvm_arch_vcpu_ioctl(filp, ioctl, arg);
> }
> @@ -4863,6 +4918,12 @@ static int kvm_vm_ioctl_check_extension_generic(struct kvm *kvm, long arg)
> #ifdef CONFIG_KVM_PRIVATE_MEM
> case KVM_CAP_GUEST_MEMFD:
> return !kvm || kvm_arch_has_private_mem(kvm);
> +#endif
> +#ifdef CONFIG_KVM_GENERIC_MAP_MEMORY
> + case KVM_CAP_MAP_MEMORY:
> + if (!kvm)
> + return 1;
> + /* Leave per-VM implementation to kvm_vm_ioctl_check_extension(). */
nitpick:
fallthough;
> #endif
> default:
> break;
> --
> 2.43.0
>
>
>
--
Isaku Yamahata <isaku.yamahata@xxxxxxxxx>
