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Handling FEAT_ATS1A (which provides the AT S1E{1,2}A instructions)
is pretty easy, as it is just the usual AT without the permission
check.
This basically amounts to plumbing the instructions in the various
dispatch tables, and handling FEAT_ATS1A being disabled in the
ID registers.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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FEAT_PAN3 added a check for executable permissions to FEAT_PAN2.
Add the required SCTLR_ELx.EPAN and descriptor checks to handle
this correctly.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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In order to plug the brokenness of our current AT implementation,
we need a SW walker that is going to... err.. walk the S1 tables
and tell us what it finds.
Of course, it builds on top of our S2 walker, and share similar
concepts. The beauty of it is that since it uses kvm_read_guest(),
it is able to bring back pages that have been otherwise evicted.
This is then plugged in the two AT S1 emulation functions as
a "slow path" fallback. I'm not sure it is that slow, but hey.
Reviewed-by: Alexandru Elisei <alexandru.elisei@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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On the face of it, AT S12E{0,1}{R,W} is pretty simple. It is the
combination of AT S1E{0,1}{R,W}, followed by an extra S2 walk.
However, there is a great deal of complexity coming from combining
the S1 and S2 attributes to report something consistent in PAR_EL1.
This is an absolute mine field, and I have a splitting headache.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Similar to our AT S1E{0,1} emulation, we implement the AT S1E2
handling.
This emulation of course suffers from the same problems, but is
somehow simpler due to the lack of PAN2 and the fact that we are
guaranteed to execute it from the correct context.
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Building on top of our primitive AT S1E{0,1}{R,W} emulation,
add minimal support for the FEAT_PAN2 instructions, momentary
context-switching PSTATE.PAN so that it takes effect in the
context of the guest.
Signed-off-by: Marc Zyngier <maz@kernel.org>
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Emulating AT instructions is one the tasks devolved to the host
hypervisor when NV is on.
Here, we take the basic approach of emulating AT S1E{0,1}{R,W}
using the AT instructions themselves. While this mostly work,
it doesn't *always* work:
- S1 page tables can be swapped out
- shadow S2 can be incomplete and not contain mappings for
the S1 page tables
We are not trying to handle these case here, and defer it to
a later patch. Suitable comments indicate where we are in dire
need of better handling.
Co-developed-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
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