[PATCH 61/89] KVM: arm64: Reset sysregs for protected VMs

[Will Deacon <will@kernel.org>]

From: Fuad Tabba <tabba@google.com>

Create a framework for resetting protected VM system registers to
their architecturally defined reset values.

No functional change intended as these are not hooked in yet.

Signed-off-by: Fuad Tabba <tabba@google.com>
---
 arch/arm64/kvm/hyp/include/nvhe/pkvm.h |  1 +
 arch/arm64/kvm/hyp/nvhe/sys_regs.c     | 84 +++++++++++++++++++++++++-
 2 files changed, 84 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
index d070400b5616..e772f9835a86 100644
--- a/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
+++ b/arch/arm64/kvm/hyp/include/nvhe/pkvm.h
@@ -98,6 +98,7 @@ struct kvm_shadow_vcpu_state *pkvm_loaded_shadow_vcpu_state(void);
 u64 pvm_read_id_reg(const struct kvm_vcpu *vcpu, u32 id);
 bool kvm_handle_pvm_sysreg(struct kvm_vcpu *vcpu, u64 *exit_code);
 bool kvm_handle_pvm_restricted(struct kvm_vcpu *vcpu, u64 *exit_code);
+void kvm_reset_pvm_sys_regs(struct kvm_vcpu *vcpu);
 int kvm_check_pvm_sysreg_table(void);
 
 #endif /* __ARM64_KVM_NVHE_PKVM_H__ */
diff --git a/arch/arm64/kvm/hyp/nvhe/sys_regs.c b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
index e732826f9624..aeea565d84b8 100644
--- a/arch/arm64/kvm/hyp/nvhe/sys_regs.c
+++ b/arch/arm64/kvm/hyp/nvhe/sys_regs.c
@@ -470,8 +470,85 @@ static const struct sys_reg_desc pvm_sys_reg_descs[] = {
 	/* Performance Monitoring Registers are restricted. */
 };
 
+/* A structure to track reset values for system registers in protected vcpus. */
+struct sys_reg_desc_reset {
+	/* Index into sys_reg[]. */
+	int reg;
+
+	/* Reset function. */
+	void (*reset)(struct kvm_vcpu *, const struct sys_reg_desc_reset *);
+
+	/* Reset value. */
+	u64 value;
+};
+
+static void reset_actlr(struct kvm_vcpu *vcpu, const struct sys_reg_desc_reset *r)
+{
+	__vcpu_sys_reg(vcpu, r->reg) = read_sysreg(actlr_el1);
+}
+
+static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc_reset *r)
+{
+	__vcpu_sys_reg(vcpu, r->reg) = read_sysreg(amair_el1);
+}
+
+static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc_reset *r)
+{
+	__vcpu_sys_reg(vcpu, r->reg) = calculate_mpidr(vcpu);
+}
+
+static void reset_value(struct kvm_vcpu *vcpu, const struct sys_reg_desc_reset *r)
+{
+	__vcpu_sys_reg(vcpu, r->reg) = r->value;
+}
+
+/* Specify the register's reset value. */
+#define RESET_VAL(REG, RESET_VAL) {  REG, reset_value, RESET_VAL }
+
+/* Specify a function that calculates the register's reset value. */
+#define RESET_FUNC(REG, RESET_FUNC) {  REG, RESET_FUNC, 0 }
+
+/*
+ * Architected system registers reset values for Protected VMs.
+ * Important: Must be sorted ascending by REG (index into sys_reg[])
+ */
+static const struct sys_reg_desc_reset pvm_sys_reg_reset_vals[] = {
+	RESET_FUNC(MPIDR_EL1, reset_mpidr),
+	RESET_VAL(SCTLR_EL1, 0x00C50078),
+	RESET_FUNC(ACTLR_EL1, reset_actlr),
+	RESET_VAL(CPACR_EL1, 0),
+	RESET_VAL(ZCR_EL1, 0),
+	RESET_VAL(TCR_EL1, 0),
+	RESET_VAL(VBAR_EL1, 0),
+	RESET_VAL(CONTEXTIDR_EL1, 0),
+	RESET_FUNC(AMAIR_EL1, reset_amair_el1),
+	RESET_VAL(CNTKCTL_EL1, 0),
+	RESET_VAL(MDSCR_EL1, 0),
+	RESET_VAL(MDCCINT_EL1, 0),
+	RESET_VAL(DISR_EL1, 0),
+	RESET_VAL(PMCCFILTR_EL0, 0),
+	RESET_VAL(PMUSERENR_EL0, 0),
+};
+
 /*
- * Checks that the sysreg table is unique and in-order.
+ * Sets system registers to reset value
+ *
+ * This function finds the right entry and sets the registers on the protected
+ * vcpu to their architecturally defined reset values.
+ */
+void kvm_reset_pvm_sys_regs(struct kvm_vcpu *vcpu)
+{
+	unsigned long i;
+
+	for (i = 0; i < ARRAY_SIZE(pvm_sys_reg_reset_vals); i++) {
+		const struct sys_reg_desc_reset *r = &pvm_sys_reg_reset_vals[i];
+
+		r->reset(vcpu, r);
+	}
+}
+
+/*
+ * Checks that the sysreg tables are unique and in-order.
  *
  * Returns 0 if the table is consistent, or 1 otherwise.
  */
@@ -484,6 +561,11 @@ int kvm_check_pvm_sysreg_table(void)
 			return 1;
 	}
 
+	for (i = 1; i < ARRAY_SIZE(pvm_sys_reg_reset_vals); i++) {
+		if (pvm_sys_reg_reset_vals[i-1].reg >= pvm_sys_reg_reset_vals[i].reg)
+			return 1;
+	}
+
 	return 0;
 }
 
-- 
2.36.1.124.g0e6072fb45-goog

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