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authorDave Martin <Dave.Martin@arm.com>2016-01-19 16:20:18 +0000
committerMarc Zyngier <marc.zyngier@arm.com>2016-01-24 21:55:58 +0000
commita7e0ac295d964086af3bf98352614f33c381213e (patch)
tree7529af0368e5df69e650d5fda9ba73b6667406c7 /arch/arm64/kvm/hyp
parent8fc153cda9c9e6aed2a4a7235970dd6c6cb6e954 (diff)
downloadop-kernel-dev-a7e0ac295d964086af3bf98352614f33c381213e.zip
op-kernel-dev-a7e0ac295d964086af3bf98352614f33c381213e.tar.gz
arm64: KVM: Obey RES0/1 reserved bits when setting CPTR_EL2
Some bits in CPTR are defined as RES1 in the architecture. Setting these bits to zero may unintentionally enable future architecture extensions, allowing guests to use them without supervision by the host. This would be bad: for forwards compatibility, this patch makes sure the affected bits are always written with 1, not 0. This patch only addresses CPTR_EL2. Initialisation of other system registers may still need review. Reviewed-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Dave Martin <Dave.Martin@arm.com> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Diffstat (limited to 'arch/arm64/kvm/hyp')
-rw-r--r--arch/arm64/kvm/hyp/switch.c8
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/arm64/kvm/hyp/switch.c b/arch/arm64/kvm/hyp/switch.c
index ca8f5a5..f0e7bdf 100644
--- a/arch/arm64/kvm/hyp/switch.c
+++ b/arch/arm64/kvm/hyp/switch.c
@@ -36,7 +36,11 @@ static void __hyp_text __activate_traps(struct kvm_vcpu *vcpu)
write_sysreg(val, hcr_el2);
/* Trap on AArch32 cp15 c15 accesses (EL1 or EL0) */
write_sysreg(1 << 15, hstr_el2);
- write_sysreg(CPTR_EL2_TTA | CPTR_EL2_TFP, cptr_el2);
+
+ val = CPTR_EL2_DEFAULT;
+ val |= CPTR_EL2_TTA | CPTR_EL2_TFP;
+ write_sysreg(val, cptr_el2);
+
write_sysreg(vcpu->arch.mdcr_el2, mdcr_el2);
}
@@ -45,7 +49,7 @@ static void __hyp_text __deactivate_traps(struct kvm_vcpu *vcpu)
write_sysreg(HCR_RW, hcr_el2);
write_sysreg(0, hstr_el2);
write_sysreg(read_sysreg(mdcr_el2) & MDCR_EL2_HPMN_MASK, mdcr_el2);
- write_sysreg(0, cptr_el2);
+ write_sysreg(CPTR_EL2_DEFAULT, cptr_el2);
}
static void __hyp_text __activate_vm(struct kvm_vcpu *vcpu)
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