Messages in this thread | | | From | "Sricharan" <> | Subject | RE: [PATCH V8 1/9] iommu: add IOMMU_PRIV attribute | Date | Fri, 6 Jan 2017 17:35:25 +0530 |
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Hi Joerg,
>-----Original Message----- >From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@lists.infradead.org] On Behalf Of Joerg Roedel >Sent: Friday, January 06, 2017 4:36 PM >To: Sricharan R <sricharan@codeaurora.org> >Cc: mitchelh@codeaurora.org; pdaly@codeaurora.org; vinod.koul@intel.com; jgebben@codeaurora.org; will.deacon@arm.com; >linux-kernel@vger.kernel.org; iommu@lists.linux-foundation.org; linux@armlinux.org.uk; jcrouse@codeaurora.org; >dan.j.williams@intel.com; pratikp@codeaurora.org; tzeng@codeaurora.org; linux-arm-kernel@lists.infradead.org; >robin.murphy@arm.com >Subject: Re: [PATCH V8 1/9] iommu: add IOMMU_PRIV attribute > >On Mon, Jan 02, 2017 at 06:42:36PM +0530, Sricharan R wrote: >> From: Mitchel Humpherys <mitchelh@codeaurora.org> >> >> Add the IOMMU_PRIV attribute, which is used to indicate privileged >> mappings. >> >> Reviewed-by: Robin Murphy <robin.murphy@arm.com> >> Tested-by: Robin Murphy <robin.murphy@arm.com> >> Signed-off-by: Mitchel Humpherys <mitchelh@codeaurora.org> >> Acked-by: Will Deacon <will.deacon@arm.com> >> --- >> include/linux/iommu.h | 1 + >> 1 file changed, 1 insertion(+) >> >> diff --git a/include/linux/iommu.h b/include/linux/iommu.h >> index 0ff5111..8c15ada 100644 >> --- a/include/linux/iommu.h >> +++ b/include/linux/iommu.h >> @@ -31,6 +31,7 @@ >> #define IOMMU_CACHE (1 << 2) /* DMA cache coherency */ >> #define IOMMU_NOEXEC (1 << 3) >> #define IOMMU_MMIO (1 << 4) /* e.g. things like MSI doorbells */ >> +#define IOMMU_PRIV (1 << 5) /* privileged */ > >Since this is a new generic global flag, can you please add a more >verbose comment telling what a 'privileged' mapping is about in the >iommu-case? We should have a clear defined semantic for this flag or we >might end up with different meanings for it with different >iommu-hardware.
This flag is to inform the iommu api to setup privileged mappings for the caller which can be accessed only by the master running with supervisor/privileged permissions and inaccessible to less privileged execution levels.
i will repost this with comment added.
Regards, Sricharan
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