From: Pierre Morel <pmorel@linux.ibm.com>
To: Halil Pasic <pasic@linux.ibm.com>
Cc: Cornelia Huck <cohuck@redhat.com>,
linux-kernel@vger.kernel.org, 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 v5 2/2] s390: virtio: PV needs VIRTIO I/O device protection
Date: Thu, 9 Jul 2020 12:58:09 +0200 [thread overview]
Message-ID: <12b1ca5c-fc03-18c7-bdca-cedabc5f1e1d@linux.ibm.com> (raw)
In-Reply-To: <20200709115553.2dde6ab1.pasic@linux.ibm.com>
On 2020-07-09 11:55, Halil Pasic wrote:
> On Thu, 9 Jul 2020 10:57:33 +0200
> Cornelia Huck <cohuck@redhat.com> wrote:
>
>> On Thu, 9 Jul 2020 10:39:19 +0200
>> Pierre Morel <pmorel@linux.ibm.com> wrote:
>>
>>> 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
>>> fail probe if that's not the case, preventing a host error on access
>>> attempt
>
> Punctuation at the end?
>
> Also 'that's not the case' refers to the negation
> 'VIRTIO_F_IOMMU_PLATFORM has been negotiated',
> arch_validate_virtio_features() is however part of
> virtio_finalize_features(), which is in turn part of the feature
> negotiation. But that is details. I'm fine with keeping the message as
> is.
>
>>>
>>> Signed-off-by: Pierre Morel <pmorel@linux.ibm.com>
>>> ---
>>> arch/s390/mm/init.c | 27 +++++++++++++++++++++++++++
>>> 1 file changed, 27 insertions(+)
>>>
>>> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
>>> index 6dc7c3b60ef6..b8e6f90117da 100644
>>> --- a/arch/s390/mm/init.c
>>> +++ b/arch/s390/mm/init.c
>>> @@ -45,6 +45,7 @@
>>> #include <asm/kasan.h>
>>> #include <asm/dma-mapping.h>
>>> #include <asm/uv.h>
>>> +#include <linux/virtio_config.h>
>>>
>>> pgd_t swapper_pg_dir[PTRS_PER_PGD] __section(.bss..swapper_pg_dir);
>>>
>>> @@ -161,6 +162,32 @@ bool force_dma_unencrypted(struct device *dev)
>>> return is_prot_virt_guest();
>>> }
>>>
>>> +/*
>>> + * arch_validate_virtio_features
>>> + * @dev: the VIRTIO device being added
>>> + *
>>> + * Return an error if required features are missing on a guest running
>>> + * with protected virtualization.
>>> + */
>>> +int arch_validate_virtio_features(struct virtio_device *dev)
>>> +{
>>> + if (!is_prot_virt_guest())
>>> + return 0;
>>> +
>>> + if (!virtio_has_feature(dev, VIRTIO_F_VERSION_1)) {
>>> + dev_warn(&dev->dev, "device must provide VIRTIO_F_VERSION_1\n");
>>
>> I'd probably use "legacy virtio not supported with protected
>> virtualization".
>>
>>> + return -ENODEV;
>>> + }
>>> +
>>> + if (!virtio_has_feature(dev, VIRTIO_F_IOMMU_PLATFORM)) {
>>> + dev_warn(&dev->dev,
>>> + "device must provide VIRTIO_F_IOMMU_PLATFORM\n");
>>
>> "support for limited memory access required for protected
>> virtualization"
>>
>> ?
>>
>> Mentioning the feature flag is shorter in both cases, though.
>
> I liked the messages in v4. Why did we change those? Did somebody
> complain?
>
> I prefer the old ones, but it any case:
>
> Acked-by: Halil Pasic <pasic@linux.ibm.com>
Thanks,
Pierre
--
Pierre Morel
IBM Lab Boeblingen
next prev parent reply other threads:[~2020-07-09 10:58 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-09 8:39 [PATCH v5 0/2] s390: virtio: let arch validate VIRTIO features Pierre Morel
2020-07-09 8:39 ` [PATCH v5 1/2] " Pierre Morel
2020-07-09 9:58 ` Halil Pasic
2020-07-09 10:48 ` Pierre Morel
2020-07-09 8:39 ` [PATCH v5 2/2] s390: virtio: PV needs VIRTIO I/O device protection Pierre Morel
2020-07-09 8:57 ` Cornelia Huck
2020-07-09 9:55 ` Halil Pasic
2020-07-09 10:58 ` Pierre Morel [this message]
2020-07-09 10:51 ` Pierre Morel
2020-07-09 14:47 ` Halil Pasic
2020-07-09 14:51 ` Pierre Morel
2020-07-09 15:06 ` Halil Pasic
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