Re: [PATCH RFC 01/14] x86/asm: add iosubmit_cmds512() based on movdir64b CPU instruction

From: Dave Jiang
Date: Thu Nov 21 2019 - 11:52:24 EST

On 11/21/19 3:59 AM, Borislav Petkov wrote:
On Wed, Nov 20, 2019 at 05:10:41PM -0700, Dave Jiang wrote:
I'll add the check on the destination address. The call is modeled after
__iowrite64_copy() / __iowrite32_copy() in lib/iomap_copy.c. Looks like
those functions do not check for the alignment requirements either.

So just because they don't check, you don't need to check either?

No what I mean was those primitives are missing the checks and we should probably address that at some point.

Can you guarantee that all callers will always do the right thing?

I mean, if you don't care too much, why even write "(must be 512-bit
aligned)"? Who cares then if the data is aligned or not...

+ * @dst: destination, in MMIO space (must be 512-bit aligned)
+ * @src: source
+ * @count: number of 512 bits quantities to submit

Where's that check on the data?

I don't follow?

What do you do if the caller doesn't submit data in 512 bits quantities?

How would I detect that? Add a size (in bytes) parameter for the total source data?