From: Cornelia Huck <cohuck@redhat.com>
To: Pierre Morel <pmorel@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org, pasic@linux.ibm.com,
borntraeger@de.ibm.com, frankja@linux.ibm.com, mst@redhat.com,
jasowang@redhat.com, kvm@vger.kernel.org,
linux-s390@vger.kernel.org,
virtualization@lists.linux-foundation.org,
thomas.lendacky@amd.com, david@gibson.dropbear.id.au,
linuxram@us.ibm.com, heiko.carstens@de.ibm.com,
gor@linux.ibm.com
Subject: Re: [PATCH v4 2/2] s390: virtio: PV needs VIRTIO I/O device protection
Date: Tue, 7 Jul 2020 11:46:33 +0200 [thread overview]
Message-ID: <20200707114633.68122a00.cohuck@redhat.com> (raw)
In-Reply-To: <1594111477-15401-3-git-send-email-pmorel@linux.ibm.com>
On Tue, 7 Jul 2020 10:44:37 +0200
Pierre Morel <pmorel@linux.ibm.com> wrote:
> S390, protecting the guest memory against unauthorized host access
> needs to enforce VIRTIO I/O device protection through the use of
> VIRTIO_F_VERSION_1 and VIRTIO_F_IOMMU_PLATFORM.
Hm... what about:
"If protected virtualization is active on s390, the virtio queues are
not accessible to the host, unless VIRTIO_F_IOMMU_PLATFORM has been
negotiated. Use the new arch_validate_virtio_features() interface to
enforce this."
>
> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
> ---
> arch/s390/kernel/uv.c | 25 +++++++++++++++++++++++++
> 1 file changed, 25 insertions(+)
>
> diff --git a/arch/s390/kernel/uv.c b/arch/s390/kernel/uv.c
> index c296e5c8dbf9..106330f6eda1 100644
> --- a/arch/s390/kernel/uv.c
> +++ b/arch/s390/kernel/uv.c
> @@ -14,6 +14,7 @@
> #include <linux/memblock.h>
> #include <linux/pagemap.h>
> #include <linux/swap.h>
> +#include <linux/virtio_config.h>
> #include <asm/facility.h>
> #include <asm/sections.h>
> #include <asm/uv.h>
> @@ -413,3 +414,27 @@ static int __init uv_info_init(void)
> }
> device_initcall(uv_info_init);
> #endif
> +
> +/*
> + * arch_validate_virtio_iommu_platform
s/arch_validate_virtio_iommu_platform/arch_validate_virtio_features/
> + * @dev: the VIRTIO device being added
> + *
> + * Return value: returns -ENODEV if any features of the
> + * device breaks the protected virtualization
> + * 0 otherwise.
I don't think you need to specify the contract here: that belongs to
the definition in the virtio core. What about simply adding a sentence
"Return an error if required features are missing on a guest running
with protected virtualization." ?
> + */
> +int arch_validate_virtio_features(struct virtio_device *dev)
> +{
Maybe jump out immediately if the guest is not protected?
> + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
> + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n");
> + return is_prot_virt_guest() ? -ENODEV : 0;
> + }
> +
> + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
> + dev_warn(&dev->dev,
> + "device must provide VIRTIO_F_IOMMU_PLATFORM\n");
> + return is_prot_virt_guest() ? -ENODEV : 0;
> + }
if (!is_prot_virt_guest())
return 0;
if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
dev_warn(&dev->dev,
"legacy virtio is incompatible with protected guests");
return -ENODEV;
}
if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
dev_warn(&dev->dev,
"device does not work with limited memory access in protected guests");
return -ENODEV;
}
> +
> + return 0;
> +}
next prev parent reply other threads:[~2020-07-07 9:46 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-07 8:44 [PATCH v4 0/2] s390: virtio: let arch validate VIRTIO features Pierre Morel
2020-07-07 8:44 ` [PATCH v4 1/2] " Pierre Morel
2020-07-07 9:26 ` Cornelia Huck
2020-07-07 10:39 ` Pierre Morel
2020-07-07 11:09 ` Christian Borntraeger
2020-07-07 11:17 ` Pierre Morel
2020-07-07 8:44 ` [PATCH v4 2/2] s390: virtio: PV needs VIRTIO I/O device protection Pierre Morel
2020-07-07 9:46 ` Cornelia Huck [this message]
2020-07-07 10:38 ` Pierre Morel
2020-07-07 11:19 ` Halil Pasic
2020-07-07 11:14 ` Michael S. Tsirkin
2020-07-07 11:19 ` Pierre Morel
2020-07-07 11:12 ` Christian Borntraeger
2020-07-07 11:16 ` Pierre Morel
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