Hi Christoph,
I am sorry, fix my typo.
Walter
On Tue, 2021-11-02 at 07:41 +0100, Christoph Hellwig wrote:
> As others pointed out, DMA_ATTR_NO_KERNEL_MAPPING just means the
> caller can't rely on a kernel mapping. So the "fix" here is
> wrong. That being said for cases where we can easily
Hi Cristoph,
On Tue, 2021-11-02 at 07:41 +0100, Christoph Hellwig wrote:
> As others pointed out, DMA_ATTR_NO_KERNEL_MAPPING just means the
> caller can't rely on a kernel mapping. So the "fix" here is
> wrong. That being said for cases where we can easily remove a page
> from the kernel
On Tue, Nov 02, 2021 at 11:21:16AM +0800, Walter Wu wrote:
> Our platform is arch64. We need a dynamic allocated buffer from CMA is
> not to read by CPU peculative execution, so we need to remove its
> kernel mapping.
If your CPU speculates into unused kernel direct mappings your have
a worse
As others pointed out, DMA_ATTR_NO_KERNEL_MAPPING just means the
caller can't rely on a kernel mapping. So the "fix" here is
wrong. That being said for cases where we can easily remove a page
from the kernel mapping it would be nice to do to:
a) improve security
b) as a debug check to see
On Mon, 2021-11-01 at 15:17 +0100, Ard Biesheuvel wrote:
> On Mon, 1 Nov 2021 at 13:21, Walter Wu
> wrote:
> >
> > Hi Ard,
> >
> > On Mon, 2021-11-01 at 09:34 +0100, Ard Biesheuvel wrote:
> > > On Mon, 1 Nov 2021 at 04:17, Walter Wu > > >
> > > wrote:
> > > >
> > > >
On Mon, 1 Nov 2021 at 13:21, Walter Wu wrote:
>
> Hi Ard,
>
> On Mon, 2021-11-01 at 09:34 +0100, Ard Biesheuvel wrote:
> > On Mon, 1 Nov 2021 at 04:17, Walter Wu
> > wrote:
> > >
> > > DMA_ATTR_NO_KERNEL_MAPPING is to avoid creating a kernel mapping
> > > for the allocated buffer, but current
Hi Ard,
On Mon, 2021-11-01 at 09:34 +0100, Ard Biesheuvel wrote:
> On Mon, 1 Nov 2021 at 04:17, Walter Wu
> wrote:
> >
> > DMA_ATTR_NO_KERNEL_MAPPING is to avoid creating a kernel mapping
> > for the allocated buffer, but current implementation is that
> > PTE of allocated buffer in kernel page
Hi Robin,
On Mon, 2021-11-01 at 10:29 +, Robin Murphy wrote:
> On 2021-11-01 03:15, Walter Wu wrote:
> > DMA_ATTR_NO_KERNEL_MAPPING is to avoid creating a kernel mapping
> > for the allocated buffer, but current implementation is that
> > PTE of allocated buffer in kernel page table is valid.
On 2021-11-01 03:15, Walter Wu wrote:
DMA_ATTR_NO_KERNEL_MAPPING is to avoid creating a kernel mapping
for the allocated buffer, but current implementation is that
PTE of allocated buffer in kernel page table is valid. So we
should set invalid for PTE of allocate buffer so that there are
no
On Mon, 1 Nov 2021 at 04:17, Walter Wu wrote:
>
> DMA_ATTR_NO_KERNEL_MAPPING is to avoid creating a kernel mapping
> for the allocated buffer, but current implementation is that
> PTE of allocated buffer in kernel page table is valid. So we
> should set invalid for PTE of allocate buffer so that
Hi Walter,
Thank you for the patch! Yet something to improve:
[auto build test ERROR on linux/master]
[also build test ERROR on linus/master v5.15 next-20211029]
[cannot apply to hch-configfs/for-next]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting
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