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Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.5.0 MIME-Version: 1.0 In-Reply-To: Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Cc: "jean-philippe@linaro.org" , "Tian, Kevin" , "Raj, Ashok" , "kvm@vger.kernel.org" , "stefanha@gmail.com" , "Tian, Jun J" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" , "Sun, Yi Y" , Robin Murphy , Will Deacon , "Wu, Hao" X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" Hi Yi, On 7/6/20 2:46 PM, Liu, Yi L wrote: > Hi Eric, > >> From: Auger Eric >> >> Hi Yi, >> >> Please add a commit message: instead of returning a boolean for >> DOMAIN_ATTR_NESTING, arm_smmu_domain_get_attr() returns a >> iommu_nesting_info handle. > > will do. thanks for the suggestion. > >> >> On 7/4/20 1:26 PM, Liu Yi L wrote: >>> Cc: Will Deacon >>> Cc: Robin Murphy >>> Cc: Eric Auger >>> Cc: Jean-Philippe Brucker >>> Suggested-by: Jean-Philippe Brucker >>> Signed-off-by: Liu Yi L >>> Signed-off-by: Jacob Pan >>> --- >>> drivers/iommu/arm-smmu-v3.c | 29 +++++++++++++++++++++++++++-- >>> drivers/iommu/arm-smmu.c | 29 +++++++++++++++++++++++++++-- >>> 2 files changed, 54 insertions(+), 4 deletions(-) >>> >>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c >>> index f578677..0c45d4d 100644 >>> --- a/drivers/iommu/arm-smmu-v3.c >>> +++ b/drivers/iommu/arm-smmu-v3.c >>> @@ -3019,6 +3019,32 @@ static struct iommu_group >> *arm_smmu_device_group(struct device *dev) >>> return group; >>> } >>> >>> +static int arm_smmu_domain_nesting_info(struct arm_smmu_domain >> *smmu_domain, >>> + void *data) >>> +{ >>> + struct iommu_nesting_info *info = (struct iommu_nesting_info *) data; >>> + u32 size; >>> + >>> + if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED) >>> + return -ENODEV; >>> + >>> + size = sizeof(struct iommu_nesting_info); >>> + >>> + /* >>> + * if provided buffer size is not equal to the size, should >>> + * return 0 and also the expected buffer size to caller. >>> + */ >>> + if (info->size != size) { >> < size? > > < size may work as well. but I'd like the caller provide exact buffer size. not sure > if it is demand in kernel. do you have any suggestion? I just suggested that by analogy with the VFIO argsz > >>> + info->size = size; >>> + return 0; >>> + } >>> + >>> + /* report an empty iommu_nesting_info for now */ >>> + memset(info, 0x0, size); >>> + info->size = size; >> For info, the current SMMU NESTED mode is not enabling any nesting. It just forces >> the usage of the 2st stage instead of stage1 for single stage translation. > > yep. The intention is as below: > > " However it requires changing the get_attr(NESTING) implementations in both > SMMU drivers as a precursor of this series, to avoid breaking > VFIO_TYPE1_NESTING_IOMMU on Arm. Since we haven't yet defined the > nesting_info structs for SMMUv2 and v3, I suppose we could return an empty > struct iommu_nesting_info for now?" > https://lore.kernel.org/linux-iommu/20200617143909.GA886590@myrica/ > > do you think any other needs to be done for now? I understand this is a prerequisite. It was more as an information. Returning a void struct is a bit weird but at the moment I don't have anything better. Thanks Eric > > Regards, > Yi Liu > >> Thanks >> >> Eric >>> + return 0; >>> +} >>> + >>> static int arm_smmu_domain_get_attr(struct iommu_domain *domain, >>> enum iommu_attr attr, void *data) { @@ - >> 3028,8 +3054,7 @@ >>> static int arm_smmu_domain_get_attr(struct iommu_domain *domain, >>> case IOMMU_DOMAIN_UNMANAGED: >>> switch (attr) { >>> case DOMAIN_ATTR_NESTING: >>> - *(int *)data = (smmu_domain->stage == >> ARM_SMMU_DOMAIN_NESTED); >>> - return 0; >>> + return arm_smmu_domain_nesting_info(smmu_domain, >> data); >>> default: >>> return -ENODEV; >>> } >>> diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c index >>> 243bc4c..908607d 100644 >>> --- a/drivers/iommu/arm-smmu.c >>> +++ b/drivers/iommu/arm-smmu.c >>> @@ -1506,6 +1506,32 @@ static struct iommu_group >> *arm_smmu_device_group(struct device *dev) >>> return group; >>> } >>> >>> +static int arm_smmu_domain_nesting_info(struct arm_smmu_domain >> *smmu_domain, >>> + void *data) >>> +{ >>> + struct iommu_nesting_info *info = (struct iommu_nesting_info *) data; >>> + u32 size; >>> + >>> + if (!info || smmu_domain->stage != ARM_SMMU_DOMAIN_NESTED) >>> + return -ENODEV; >>> + >>> + size = sizeof(struct iommu_nesting_info); >>> + >>> + /* >>> + * if provided buffer size is not equal to the size, should >>> + * return 0 and also the expected buffer size to caller. >>> + */ >>> + if (info->size != size) { >>> + info->size = size; >>> + return 0; >>> + } >>> + >>> + /* report an empty iommu_nesting_info for now */ >>> + memset(info, 0x0, size); >>> + info->size = size; >>> + return 0; >>> +} >>> + >>> static int arm_smmu_domain_get_attr(struct iommu_domain *domain, >>> enum iommu_attr attr, void *data) { @@ - >> 1515,8 +1541,7 @@ >>> static int arm_smmu_domain_get_attr(struct iommu_domain *domain, >>> case IOMMU_DOMAIN_UNMANAGED: >>> switch (attr) { >>> case DOMAIN_ATTR_NESTING: >>> - *(int *)data = (smmu_domain->stage == >> ARM_SMMU_DOMAIN_NESTED); >>> - return 0; >>> + return arm_smmu_domain_nesting_info(smmu_domain, >> data); >>> default: >>> return -ENODEV; >>> } >>> > _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu