[PATCH v6 16/26] KVM: arm64: Provide I-cache invalidation by virtual address at EL2

[Will Deacon]

In preparation for handling cache maintenance of guest pages from within
the pKVM hypervisor at EL2, introduce an EL2 copy of icache_inval_pou()
which will later be plumbed into the stage-2 page-table cache
maintenance callbacks, ensuring that the initial contents of pages
mapped as executable into the guest stage-2 page-table is visible to the
instruction fetcher.

Tested-by: Vincent Donnefort <vdonnefort at google.com>
Signed-off-by: Will Deacon <will at kernel.org>
---
 arch/arm64/include/asm/kvm_hyp.h |  1 +
 arch/arm64/kernel/image-vars.h   |  3 ---
 arch/arm64/kvm/arm.c             |  1 +
 arch/arm64/kvm/hyp/nvhe/cache.S  | 11 +++++++++++
 arch/arm64/kvm/hyp/nvhe/pkvm.c   |  3 +++
 5 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/arch/arm64/include/asm/kvm_hyp.h b/arch/arm64/include/asm/kvm_hyp.h
index aa7fa2a08f06..fd99cf09972d 100644
--- a/arch/arm64/include/asm/kvm_hyp.h
+++ b/arch/arm64/include/asm/kvm_hyp.h
@@ -123,4 +123,5 @@ extern u64 kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val);
 extern u64 kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val);
 extern u64 kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val);
 
+extern unsigned long kvm_nvhe_sym(__icache_flags);
 #endif /* __ARM64_KVM_HYP_H__ */
diff --git a/arch/arm64/kernel/image-vars.h b/arch/arm64/kernel/image-vars.h
index 8151412653de..7f4e43bfaade 100644
--- a/arch/arm64/kernel/image-vars.h
+++ b/arch/arm64/kernel/image-vars.h
@@ -71,9 +71,6 @@ KVM_NVHE_ALIAS(nvhe_hyp_panic_handler);
 /* Vectors installed by hyp-init on reset HVC. */
 KVM_NVHE_ALIAS(__hyp_stub_vectors);
 
-/* Kernel symbol used by icache_is_vpipt(). */
-KVM_NVHE_ALIAS(__icache_flags);
-
 /* VMID bits set by the KVM VMID allocator */
 KVM_NVHE_ALIAS(kvm_arm_vmid_bits);
 
diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 584626e11797..d99e93e6ddf7 100644
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1894,6 +1894,7 @@ static void kvm_hyp_init_symbols(void)
 	kvm_nvhe_sym(id_aa64mmfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR0_EL1);
 	kvm_nvhe_sym(id_aa64mmfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR1_EL1);
 	kvm_nvhe_sym(id_aa64mmfr2_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64MMFR2_EL1);
+	kvm_nvhe_sym(__icache_flags) = __icache_flags;
 }
 
 static int kvm_hyp_init_protection(u32 hyp_va_bits)
diff --git a/arch/arm64/kvm/hyp/nvhe/cache.S b/arch/arm64/kvm/hyp/nvhe/cache.S
index 0c367eb5f4e2..85936c17ae40 100644
--- a/arch/arm64/kvm/hyp/nvhe/cache.S
+++ b/arch/arm64/kvm/hyp/nvhe/cache.S
@@ -12,3 +12,14 @@ SYM_FUNC_START(__pi_dcache_clean_inval_poc)
 	ret
 SYM_FUNC_END(__pi_dcache_clean_inval_poc)
 SYM_FUNC_ALIAS(dcache_clean_inval_poc, __pi_dcache_clean_inval_poc)
+
+SYM_FUNC_START(__pi_icache_inval_pou)
+alternative_if ARM64_HAS_CACHE_DIC
+	isb
+	ret
+alternative_else_nop_endif
+
+	invalidate_icache_by_line x0, x1, x2, x3
+	ret
+SYM_FUNC_END(__pi_icache_inval_pou)
+SYM_FUNC_ALIAS(icache_inval_pou, __pi_icache_inval_pou)
diff --git a/arch/arm64/kvm/hyp/nvhe/pkvm.c b/arch/arm64/kvm/hyp/nvhe/pkvm.c
index 80b8fb5b79fd..212752c48506 100644
--- a/arch/arm64/kvm/hyp/nvhe/pkvm.c
+++ b/arch/arm64/kvm/hyp/nvhe/pkvm.c
@@ -12,6 +12,9 @@
 #include <nvhe/pkvm.h>
 #include <nvhe/trap_handler.h>
 
+/* Used by icache_is_vpipt(). */
+unsigned long __icache_flags;
+
 /*
  * Set trap register values based on features in ID_AA64PFR0.
  */
-- 
2.38.1.431.g37b22c650d-goog