From: Oliver Upton <oliver.upton@xxxxxxxxx>
The debug architecture is mandatory in ARMv8, so KVM should not allow
userspace to configure a vCPU with less than that. Of course, this isn't
handled elegantly by the generic ID register plumbing, as the respective
ID register fields have a nonzero starting value.
Add an explicit check for debug versions less than v8 of the
architecture.
Signed-off-by: Oliver Upton <oliver.upton@xxxxxxxxx>
Signed-off-by: Jing Zhang <jingzhangos@xxxxxxxxxx>
---
arch/arm64/kvm/sys_regs.c | 12 ++++++++++++
1 file changed, 12 insertions(+)
diff --git a/arch/arm64/kvm/sys_regs.c b/arch/arm64/kvm/sys_regs.c
index 0160ef9cfe18..c44504038ae9 100644
--- a/arch/arm64/kvm/sys_regs.c
+++ b/arch/arm64/kvm/sys_regs.c
@@ -1496,6 +1496,7 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
const struct sys_reg_desc *rd,
u64 val)
{
+ u8 debugver = SYS_FIELD_GET(ID_AA64DFR0_EL1, DebugVer, val);
u8 pmuver = SYS_FIELD_GET(ID_AA64DFR0_EL1, PMUVer, val);
/*
@@ -1515,6 +1516,13 @@ static int set_id_aa64dfr0_el1(struct kvm_vcpu *vcpu,
if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
val &= ~ID_AA64DFR0_EL1_PMUVer_MASK;
+ /*
+ * ID_AA64DFR0_EL1.DebugVer is one of those awkward fields with a
+ * nonzero minimum safe value.
+ */
+ if (debugver < ID_AA64DFR0_EL1_DebugVer_IMP)
+ return -EINVAL;
+
return set_id_reg(vcpu, rd, val);
}
@@ -1536,6 +1544,7 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
u64 val)
{
u8 perfmon = SYS_FIELD_GET(ID_DFR0_EL1, PerfMon, val);
+ u8 copdbg = SYS_FIELD_GET(ID_DFR0_EL1, CopDbg, val);
if (perfmon == ID_DFR0_EL1_PerfMon_IMPDEF) {
val &= ~ID_DFR0_EL1_PerfMon_MASK;
@@ -1551,6 +1560,9 @@ static int set_id_dfr0_el1(struct kvm_vcpu *vcpu,
if (perfmon != 0 && perfmon < ID_DFR0_EL1_PerfMon_PMUv3)
return -EINVAL;
+ if (copdbg < ID_DFR0_EL1_CopDbg_Armv8)
+ return -EINVAL;
+
return set_id_reg(vcpu, rd, val);
}
--
2.41.0.255.g8b1d071c50-goog
