[PATCH v4 16/25] KVM: arm64: Provide I-cache invalidation by virtual address at EL2

Will Deacon
2022-10-17T12:01:00Z

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@google.com>
Signed-off-by: Will Deacon <will@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 5970fd1adbfb..2156ce546d90 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.
*/
--
2.38.0.413.g74048e4d9e-goog