KVM: arm64: Initialise hypervisor copies of host symbols unconditionally

The nVHE object at EL2 maintains its own copies of some host variables
so that, when pKVM is enabled, the host cannot directly modify the
hypervisor state. When running in normal nVHE mode, however, these
variables are still mirrored at EL2 but are not initialised.

Initialise the hypervisor symbols from the host copies regardless of
pKVM, ensuring that any reference to this data at EL2 with normal nVHE
will return a sensibly initialised value.

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20221110190259.26861-16-will@kernel.org

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 30d6fc5d3a93d8cad5b2419593f3f8ad04f8aac8..584626e11797f6c200d8785468a51eea223ea2b5 100644 (file)
--- a/arch/arm64/kvm/arm.c
+++ b/arch/arm64/kvm/arm.c
@@ -1884,11 +1884,8 @@ static int do_pkvm_init(u32 hyp_va_bits)
        return ret;
 }
 
-static int kvm_hyp_init_protection(u32 hyp_va_bits)
+static void kvm_hyp_init_symbols(void)
 {
-       void *addr = phys_to_virt(hyp_mem_base);
-       int ret;
-
        kvm_nvhe_sym(id_aa64pfr0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64PFR0_EL1);
        kvm_nvhe_sym(id_aa64pfr1_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64PFR1_EL1);
        kvm_nvhe_sym(id_aa64isar0_el1_sys_val) = read_sanitised_ftr_reg(SYS_ID_AA64ISAR0_EL1);
@@ -1897,6 +1894,12 @@ static int kvm_hyp_init_protection(u32 hyp_va_bits)
        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);
+}
+
+static int kvm_hyp_init_protection(u32 hyp_va_bits)
+{
+       void *addr = phys_to_virt(hyp_mem_base);
+       int ret;
 
        ret = create_hyp_mappings(addr, addr + hyp_mem_size, PAGE_HYP);
        if (ret)
@@ -2071,6 +2074,8 @@ static int init_hyp_mode(void)
                cpu_prepare_hyp_mode(cpu);
        }
 
+       kvm_hyp_init_symbols();
+
        if (is_protected_kvm_enabled()) {
                init_cpu_logical_map();
 
@@ -2078,9 +2083,7 @@ static int init_hyp_mode(void)
                        err = -ENODEV;
                        goto out_err;
                }
-       }
 
-       if (is_protected_kvm_enabled()) {
                err = kvm_hyp_init_protection(hyp_va_bits);
                if (err) {
                        kvm_err("Failed to init hyp memory protection\n");