[PATCH 3/3] fs/core/vmcore: Move sev_active() reference to x86 arch code
Thiago Jung Bauermann
bauerman at linux.ibm.com
Sat Jul 13 07:55:47 AEST 2019
[ Cc'ing Tom Lendacky which I forgot to do earlier. Sorry about that. ]
Thanks for the quick review.
Halil Pasic <pasic at linux.ibm.com> writes:
> On Fri, 12 Jul 2019 02:36:31 -0300
> Thiago Jung Bauermann <bauerman at linux.ibm.com> wrote:
>> Secure Encrypted Virtualization is an x86-specific feature, so it shouldn't
>> appear in generic kernel code because it forces non-x86 architectures to
>> define the sev_active() function, which doesn't make a lot of sense.
> sev_active() might be just bad (too specific) name for a general
> concept. s390 code defines it drives the right behavior in
> kernel/dma/direct.c (which uses it).
I thought about that but couldn't put my finger on a general concept.
Is it "guest with memory inaccessible to the host"?
Since your proposed definiton for force_dma_unencrypted() is simply to
make it equivalent to sev_active(), I thought it was more
straightforward to make each arch define force_dma_unencrypted()
Also, does sev_active() drive the right behavior for s390 in
elfcorehdr_read() as well?
>> To solve this problem, add an x86 elfcorehdr_read() function to override
>> the generic weak implementation. To do that, it's necessary to make
>> read_from_oldmem() public so that it can be used outside of vmcore.c.
>> Signed-off-by: Thiago Jung Bauermann <bauerman at linux.ibm.com>
>> arch/x86/kernel/crash_dump_64.c | 5 +++++
>> fs/proc/vmcore.c | 8 ++++----
>> include/linux/crash_dump.h | 14 ++++++++++++++
>> include/linux/mem_encrypt.h | 1 -
>> 4 files changed, 23 insertions(+), 5 deletions(-)
> Does not seem to apply to today's or yesterdays master.
It assumes the presence of the two patches I mentioned in the cover
letter. Only one of them is in master.
I hadn't realized the s390 virtio patches were on their way to upstream.
I was keeping an eye on the email thread but didn't see they were picked
up in the s390 pull request. I'll add a new patch to this series making
the corresponding changes to s390's <asm/mem_encrypt.h> as well.
Thiago Jung Bauermann
IBM Linux Technology Center
More information about the Linuxppc-dev