On Tue, Jun 1, 2021 at 8:38 AM Marc Zyngier [off-list ref] wrote:

On Thu, 27 May 2021 16:05:12 +0100,
Pavel Tatashin [off-list ref] wrote:

quoted

Replace places that contain logic like this:
      is_hyp_mode_available() && !is_kernel_in_hyp_mode()

With a dedicated boolean function  is_hyp_callable(). This will be needed
later in kexec in order to sooner switch back to EL2.

This looks like the very definition of "run in nVHE mode", so I'd
rather you call it like this, rather than "callable", which is
extremely ambiguous (if running at EL2, I call it any time I want, for
free).

Hi Marc,

Naming is hard. Are you proposing  s/is_hyp_callable/run_in_nvhe_mode/
? This is also not a very good name because it does not sound like a
boolean, but instead that we know that there is nvhe mode available
and we can switch to it.

quoted

Suggested-by: James Morse <james.morse@arm.com>

[Fixed merging issues]

Signed-off-by: Pavel Tatashin <pasha.tatashin@soleen.com>
---
 arch/arm64/include/asm/virt.h | 5 +++++
 arch/arm64/kernel/cpu-reset.h | 3 +--
 arch/arm64/kernel/hibernate.c | 9 +++------
 arch/arm64/kernel/sdei.c      | 2 +-
 4 files changed, 10 insertions(+), 9 deletions(-)

diff --git a/arch/arm64/include/asm/virt.h b/arch/arm64/include/asm/virt.h
index 7379f35ae2c6..4216c8623538 100644
--- a/arch/arm64/include/asm/virt.h
+++ b/arch/arm64/include/asm/virt.h

@@ -128,6 +128,11 @@ static __always_inline bool is_protected_kvm_enabled(void)
              return cpus_have_final_cap(ARM64_KVM_PROTECTED_MODE);
 }

+static inline bool is_hyp_callable(void)
+{
+     return is_hyp_mode_available() && !is_kernel_in_hyp_mode();
+}

nit: consider switching the two members of the expression so that you
don't have extra memory accesses when running at EL2.

Sure, I will do that.

quoted

-/* Do we need to reset el2? */
-#define el2_reset_needed() (is_hyp_mode_available() && !is_kernel_in_hyp_mode())
-

Please keep the macro, as it explains *why* we're doing things (we
need to reset EL2), and replacing it with a generic macro drops the
documentation aspect.

OK, I will keep the macro, and redefine it to use the common macro.

Thank you,
Pasha

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