Hello,
I would like to request 2a355ec25729 ("arm64: kpti: Whitelist Cortex-A CPUs that don't implement the CSV3 field")
to be backported to 4.19 stable.
These CPUs are not susceptible to Meltdown, so enabling the mitigations for Meltdown (kpti) should be redundant, especially since we know that it can have a huge performance penalty for certain workloads.
kpti will still be automatically enabled if KASLR is enabled.
Kind regards, Niklas
On Mon, Sep 09, 2019 at 02:45:01PM +0200, Niklas Cassel wrote:
Hello,
I would like to request 2a355ec25729 ("arm64: kpti: Whitelist Cortex-A CPUs that don't implement the CSV3 field")
to be backported to 4.19 stable.
These CPUs are not susceptible to Meltdown, so enabling the mitigations for Meltdown (kpti) should be redundant, especially since we know that it can have a huge performance penalty for certain workloads.
kpti will still be automatically enabled if KASLR is enabled.
Now queued up, thanks.
greg k-h
On Thu, Sep 19, 2019 at 10:32:47PM +0200, Greg KH wrote:
On Mon, Sep 09, 2019 at 02:45:01PM +0200, Niklas Cassel wrote:
Hello,
I would like to request 2a355ec25729 ("arm64: kpti: Whitelist Cortex-A CPUs that don't implement the CSV3 field")
to be backported to 4.19 stable.
These CPUs are not susceptible to Meltdown, so enabling the mitigations for Meltdown (kpti) should be redundant, especially since we know that it can have a huge performance penalty for certain workloads.
kpti will still be automatically enabled if KASLR is enabled.
Now queued up, thanks.
Hello Greg, Will,
How about applying this also to v4.14 stable? (Since kpti is also enabled on Cortex-A CPUs in v4.14.)
2a355ec25729 does not apply cleanly on v4.14.y, since a LOT of things have changed in the file.
git log --oneline 2a355ec25729053bb9a1a89b6c1d1cdd6c3b3fb1 --not linux-stable/linux-4.14.y arch/arm64/kernel/cpufeature.c | wc -l 72
However, I've attached a simple backport of the commit.
Kind regards, Niklas
On Wed, Sep 25, 2019 at 01:17:24AM +0200, Niklas Cassel wrote:
On Thu, Sep 19, 2019 at 10:32:47PM +0200, Greg KH wrote:
On Mon, Sep 09, 2019 at 02:45:01PM +0200, Niklas Cassel wrote:
Hello,
I would like to request 2a355ec25729 ("arm64: kpti: Whitelist Cortex-A CPUs that don't implement the CSV3 field")
to be backported to 4.19 stable.
These CPUs are not susceptible to Meltdown, so enabling the mitigations for Meltdown (kpti) should be redundant, especially since we know that it can have a huge performance penalty for certain workloads.
kpti will still be automatically enabled if KASLR is enabled.
Now queued up, thanks.
Hello Greg, Will,
How about applying this also to v4.14 stable? (Since kpti is also enabled on Cortex-A CPUs in v4.14.)
2a355ec25729 does not apply cleanly on v4.14.y, since a LOT of things have changed in the file.
git log --oneline 2a355ec25729053bb9a1a89b6c1d1cdd6c3b3fb1 --not linux-stable/linux-4.14.y arch/arm64/kernel/cpufeature.c | wc -l 72
However, I've attached a simple backport of the commit.
Thanks for the backport, now queued up.
greg k-h
linux-stable-mirror@lists.linaro.org
-
Greg KH -
Niklas Cassel