[PATCH v4 15/25] KVM: arm64: Initialise hypervisor copies of host symbols unconditionally

From: Will Deacon <will@kernel.org>
To: kvmarm@lists.linux.dev
Cc: Will Deacon <will@kernel.org>,
	Sean Christopherson <seanjc@google.com>,
	Vincent Donnefort <vdonnefort@google.com>,
	Alexandru Elisei <alexandru.elisei@arm.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	James Morse <james.morse@arm.com>,
	Chao Peng <chao.p.peng@linux.intel.com>,
	Quentin Perret <qperret@google.com>,
	Suzuki K Poulose <suzuki.poulose@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Fuad Tabba <tabba@google.com>,
	Oliver Upton <oliver.upton@linux.dev>,
	Marc Zyngier <maz@kernel.org>,
	kernel-team@android.com, kvm@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org
Subject: [PATCH v4 15/25] KVM: arm64: Initialise hypervisor copies of host symbols unconditionally
Date: Mon, 17 Oct 2022 12:51:59 +0100	[thread overview]
Message-ID: <20221017115209.2099-16-will@kernel.org> (raw)
In-Reply-To: <20221017115209.2099-1-will@kernel.org>

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.

Tested-by: Vincent Donnefort <vdonnefort@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
---
 arch/arm64/kvm/arm.c | 15 +++++++++------
 1 file changed, 9 insertions(+), 6 deletions(-)

diff --git a/arch/arm64/kvm/arm.c b/arch/arm64/kvm/arm.c
index 30d6fc5d3a93..584626e11797 100644
--- 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");
-- 
2.38.0.413.g74048e4d9e-goog

