Re: [PATCH v2 11/16] KVM: introduce a 'mmap' method for KVM devices
From: David Gibson <hidden>
Date: 2019-02-25 04:14:07
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kvm
On Fri, Feb 22, 2019 at 12:28:35PM +0100, Cédric Le Goater wrote:
Some KVM devices will want to handle special mappings related to the underlying HW. For instance, the XIVE interrupt controller of the POWER9 processor has MMIO pages for thread interrupt management and for interrupt source control that need to be exposed to the guest when the OS has the required support. Signed-off-by: Cédric Le Goater <clg@kaod.org>
Ah, when I suggested mmap() on the base device fd, I hadn't realized there wasn't a facility for that yet. Have you discussed this with Paolo? We'll need some core KVM buy in to merge this.
quoted hunk ↗ jump to hunk
--- include/linux/kvm_host.h | 1 + virt/kvm/kvm_main.c | 11 +++++++++++ 2 files changed, 12 insertions(+)diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h index c38cc5eb7e73..cbf81487b69f 100644 --- a/include/linux/kvm_host.h +++ b/include/linux/kvm_host.h@@ -1223,6 +1223,7 @@ struct kvm_device_ops { int (*has_attr)(struct kvm_device *dev, struct kvm_device_attr *attr); long (*ioctl)(struct kvm_device *dev, unsigned int ioctl, unsigned long arg); + int (*mmap)(struct kvm_device *dev, struct vm_area_struct *vma); }; void kvm_device_get(struct kvm_device *dev);diff --git a/virt/kvm/kvm_main.c b/virt/kvm/kvm_main.c index 585845203db8..84717d8cb5e4 100644 --- a/virt/kvm/kvm_main.c +++ b/virt/kvm/kvm_main.c@@ -2878,6 +2878,16 @@ static long kvm_vcpu_compat_ioctl(struct file *filp, } #endif +static int kvm_device_mmap(struct file *filp, struct vm_area_struct *vma) +{ + struct kvm_device *dev = filp->private_data; + + if (dev->ops->mmap) + return dev->ops->mmap(dev, vma); + + return -ENODEV; +} + static int kvm_device_ioctl_attr(struct kvm_device *dev, int (*accessor)(struct kvm_device *dev, struct kvm_device_attr *attr),@@ -2927,6 +2937,7 @@ static const struct file_operations kvm_device_fops = { .unlocked_ioctl = kvm_device_ioctl, .release = kvm_device_release, KVM_COMPAT(kvm_device_ioctl), + .mmap = kvm_device_mmap, }; struct kvm_device *kvm_device_from_filp(struct file *filp)
-- 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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