> -----Original Message----- > From: Lorenzo Pieralisi [mailto:lorenzo.pieralisi@xxxxxxx] > Sent: Monday, August 07, 2017 6:09 PM > To: Shameerali Kolothum Thodi > Cc: Robin Murphy; marc.zyngier@xxxxxxx; sudeep.holla@xxxxxxx; > will.deacon@xxxxxxx; hanjun.guo@xxxxxxxxxx; Gabriele Paoloni; John Garry; > Linuxarm; linux-acpi@xxxxxxxxxxxxxxx; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; > Wangzhou (B); Guohanjun (Hanjun Guo); linux-arm- > kernel@xxxxxxxxxxxxxxxxxxx; devel@xxxxxxxxxx > Subject: Re: [PATCH v5 1/2] ACPI/IORT: Add ITS address regions reservation > helper > > On Mon, Aug 07, 2017 at 08:21:40AM +0000, Shameerali Kolothum Thodi > wrote: > > > > > > > -----Original Message----- > > > From: Robin Murphy [mailto:robin.murphy@xxxxxxx] > > > Sent: Friday, August 04, 2017 5:57 PM > > > To: Shameerali Kolothum Thodi; lorenzo.pieralisi@xxxxxxx; > > > marc.zyngier@xxxxxxx; sudeep.holla@xxxxxxx; will.deacon@xxxxxxx; > > > hanjun.guo@xxxxxxxxxx > > > Cc: Gabriele Paoloni; John Garry; iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx; > linux- > > > arm-kernel@xxxxxxxxxxxxxxxxxxx; linux-acpi@xxxxxxxxxxxxxxx; > > > devel@xxxxxxxxxx; Linuxarm; Wangzhou (B); Guohanjun (Hanjun Guo) > > > Subject: Re: [PATCH v5 1/2] ACPI/IORT: Add ITS address regions > reservation > > > helper > > > > > > On 01/08/17 11:49, Shameer Kolothum wrote: > > > > On some platforms ITS address regions have to be excluded from > normal > > > > IOVA allocation in that they are detected and decoded in a HW specific > > > > way by system components and so they cannot be considered normal > > > IOVA > > > > address space. > > > > > > > > Add an helper function that retrieves ITS address regions through IORT > > > > device <-> ITS mappings and reserves it so that these regions will not > > > > be translated by IOMMU and will be excluded from IOVA allocations. > > > > > > I've just realised that we no longer seem to have a check that ensures > > > the regions are only reserved on platforms that need it - if not, then > > > we're going to break everything else that does have an ITS behind SMMU > > > translation as expected. > > > > Right. I had this doubt, but then my thinking was that we will have the > SW_MSI > > regions for those and will end up using that. But that doesn’t seems > > to be the case now. > > > > > It feels like IORT should know enough to be able to make that decision > > > internally, but if not (or if it would be hideous to do so), then I > > > guess my idea for patch #2 was a bust and we probably do need to go > back > > > to calling directly from the SMMU driver based on the SMMU model. > > > > It might be possible to do that check inside iort code, but then we have to > find > > the smmu node first and check the model number. I think it will be more > > cleaner if SMMU driver makes that check and call the > > iommu_dma_get_msi_resv_regions(). > > +1 on this one - we can do it in IORT but I think it is more logical > to have a flag in the SMMU driver (keeping the DT/ACPI fwnode switch in > generic IOMMU layer though). Please find [1] for the generic iommu helper function which will be called from SMMU driver based on the model. > Side note I: AFAICS iommu_dma_get_resv_regions() is only used on ARM, if > it is not patch 2 would break miserably on arches that do not select > IORT - you should rework the return code on !CONFIG_ACPI_IORT configs. Yes. But so far it is only used on ARM. In any way this function is not going to be changed and will introduce a new iommu_dma_get_msi_resv_regions() fn as proposed in [1]. Please take a look and let me know. I will submit the series again if this is fine. Thanks, Shameer [1] This will replace patch 2 and will be followed by smmu driver patch to invoke iommu_dma_get_msi_resv_regions() based on SMMU model. -->8-- Subject: [PATCH] iommu/dma: Add a helper function to reserve HW MSI address regions for IOMMU drivers IOMMU drivers can use this to implement their .get_resv_regions callback for HW MSI specific reservations(e.g. ARM GICv3 ITS MSI region). Signed-off-by: Shameer Kolothum <shameerali.kolothum.thodi@xxxxxxxxxx> --- drivers/iommu/dma-iommu.c | 19 +++++++++++++++++++ include/linux/dma-iommu.h | 7 +++++++ 2 files changed, 26 insertions(+) diff --git a/drivers/iommu/dma-iommu.c b/drivers/iommu/dma-iommu.c index 9d1cebe..952ecdd 100644 --- a/drivers/iommu/dma-iommu.c +++ b/drivers/iommu/dma-iommu.c @@ -19,6 +19,7 @@ * along with this program. If not, see <http://www.gnu.org/licenses/>. */ +#include <linux/acpi_iort.h> #include <linux/device.h> #include <linux/dma-iommu.h> #include <linux/gfp.h> @@ -198,6 +199,24 @@ void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list) } EXPORT_SYMBOL(iommu_dma_get_resv_regions); +/** + * iommu_dma_get_msi_resv_regions - Reserved region driver helper + * @dev: Device from iommu_get_resv_regions() + * @list: Reserved region list from iommu_get_resv_regions() + * + * IOMMU drivers can use this to implement their .get_resv_regions + * callback for HW MSI specific reservations. For now, this only + * covers ITS MSI region reservation using ACPI IORT helper function. + */ +int iommu_dma_get_msi_resv_regions(struct device *dev, struct list_head *list) +{ + if (!is_of_node(dev->iommu_fwspec->iommu_fwnode)) + return iort_iommu_its_get_resv_regions(dev, list); + + return -ENODEV; +} +EXPORT_SYMBOL(iommu_dma_get_msi_resv_regions); + static int cookie_init_hw_msi_region(struct iommu_dma_cookie *cookie, phys_addr_t start, phys_addr_t end) { diff --git a/include/linux/dma-iommu.h b/include/linux/dma-iommu.h index 92f2083..6062ef0 100644 --- a/include/linux/dma-iommu.h +++ b/include/linux/dma-iommu.h @@ -74,6 +74,8 @@ void iommu_dma_unmap_resource(struct device *dev, dma_addr_t handle, void iommu_dma_map_msi_msg(int irq, struct msi_msg *msg); void iommu_dma_get_resv_regions(struct device *dev, struct list_head *list); +int iommu_dma_get_msi_resv_regions(struct device *dev, struct list_head *list); + #else struct iommu_domain; @@ -107,6 +109,11 @@ static inline void iommu_dma_get_resv_regions(struct device *dev, struct list_he { } +static inline int iommu_dma_get_msi_resv_regions(struct device *dev, struct list_head *list) +{ + return -ENODEV; +} + #endif /* CONFIG_IOMMU_DMA */ #endif /* __KERNEL__ */ #endif /* __DMA_IOMMU_H */ -- 1.9.1 ��.n��������+%������w��{.n�����{�����ܨ}���Ơz�j:+v�����w����ޙ��&�)ߡ�a����z�ޗ���ݢj��w�f
