Subject: [PATCH v2 07/94] KVM: arm64: nv: Reset VMPIDR_EL2 and VPIDR_EL2 to sane values

From: Marc Zyngier <[email-masked]>
Date: Tue, 11 Feb 2020 17:48:11 +0000

The VMPIDR_EL2 and VPIDR_EL2 are architecturally UNKNOWN at reset, but
let's be nice to a guest hypervisor behaving foolishly and reset these
to something reasonable anyway.

Signed-off-by: Christoffer Dall <[email-masked]>
Signed-off-by: Marc Zyngier <[email-masked]>
---
 arch/arm64/kvm/sys_regs.c | 25 +++++++++++++++++++++----
 1 file changed, 21 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index b00a4aeb2a2e..4b5310ea3bf8 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -624,7 +624,7 @@ static void reset_amair_el1(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	vcpu_write_sys_reg(vcpu, amair, AMAIR_EL1);
 }
 
-static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+static u64 compute_reset_mpidr(struct kvm_vcpu *vcpu)
 {
 	u64 mpidr;
 
@@ -638,7 +638,24 @@ static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
 	mpidr = (vcpu->vcpu_id & 0x0f) << MPIDR_LEVEL_SHIFT(0);
 	mpidr |= ((vcpu->vcpu_id >> 4) & 0xff) << MPIDR_LEVEL_SHIFT(1);
 	mpidr |= ((vcpu->vcpu_id >> 12) & 0xff) << MPIDR_LEVEL_SHIFT(2);
-	vcpu_write_sys_reg(vcpu, (1ULL << 31) | mpidr, MPIDR_EL1);
+	mpidr |= (1ULL << 31);
+
+	return mpidr;
+}
+
+static void reset_mpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), MPIDR_EL1);
+}
+
+static void reset_vmpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	vcpu_write_sys_reg(vcpu, compute_reset_mpidr(vcpu), VMPIDR_EL2);
+}
+
+static void reset_vpidr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
+{
+	vcpu_write_sys_reg(vcpu, read_cpuid_id(), VPIDR_EL2);
 }
 
 static void reset_pmcr(struct kvm_vcpu *vcpu, const struct sys_reg_desc *r)
@@ -1672,8 +1689,8 @@ static const struct sys_reg_desc sys_reg_descs[] = {
 	 */
 	{ SYS_DESC(SYS_PMCCFILTR_EL0), access_pmu_evtyper, reset_val, PMCCFILTR_EL0, 0 },
 
-	{ SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_val, VPIDR_EL2, 0 },
-	{ SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_val, VMPIDR_EL2, 0 },
+	{ SYS_DESC(SYS_VPIDR_EL2), access_rw, reset_vpidr, VPIDR_EL2 },
+	{ SYS_DESC(SYS_VMPIDR_EL2), access_rw, reset_vmpidr, VMPIDR_EL2 },
 
 	{ SYS_DESC(SYS_SCTLR_EL2), access_rw, reset_val, SCTLR_EL2, 0 },
 	{ SYS_DESC(SYS_ACTLR_EL2), access_rw, reset_val, ACTLR_EL2, 0 },
-- 
2.20.1

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