KVM: arm64: Drop is_kernel_in_hyp_mode() from __invalidate_icache_guest_page()

It is pretty obvious that is_kernel_in_hyp_mode() doesn't make much
sense in the hypervisor part of KVM, and should be reserved to the
kernel side.

However, mem_protect.c::invalidate_icache_guest_page() calls into
__invalidate_icache_guest_page(), which uses is_kernel_in_hyp_mode().
Given that this is part of the pKVM side of the hypervisor, this
helper can only return true.

Nothing goes really bad, but __invalidate_icache_guest_page() could
spell out what the actual check is: we cannot invalidate the cache
if the i-cache is VPIPT and we're running at EL1.

Drop the is_kernel_in_hyp_mode() check for an explicit check against
CurrentEL being EL1 or not.

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20230609162200.2024064-2-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/include/asm/kvm_mmu.h b/arch/arm64/include/asm/kvm_mmu.h
index 27e63c1..c8113b9 100644 (file)
--- a/arch/arm64/include/asm/kvm_mmu.h
+++ b/arch/arm64/include/asm/kvm_mmu.h
@@ -227,7 +227,8 @@ static inline void __invalidate_icache_guest_page(void *va, size_t size)
        if (icache_is_aliasing()) {
                /* any kind of VIPT cache */
                icache_inval_all_pou();
-       } else if (is_kernel_in_hyp_mode() || !icache_is_vpipt()) {
+       } else if (read_sysreg(CurrentEL) != CurrentEL_EL1 ||
+                  !icache_is_vpipt()) {
                /* PIPT or VPIPT at EL2 (see comment in __kvm_tlb_flush_vmid_ipa) */
                icache_inval_pou((unsigned long)va, (unsigned long)va + size);
        }