Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
KVM: arm64: Handle FEAT_IDST for sysregs without specific handlers
Add a bit of infrastrtcture to triage_sysreg_trap() to handle the
case of registers falling into the Feature ID space that do not
have a local handler.
For these, we can directly apply the FEAT_IDST semantics and inject
an EC=0x18 exception. Otherwise, an UNDEF will do.
Reviewed-by: Joey Gouly <joey.gouly@arm.com>
Reviewed-by: Yuan Yao <yaoyuan@linux.alibaba.com>
Link: https://patch.msgid.link/20260108173233.2911955-5-maz@kernel.org
Signed-off-by: Marc Zyngier <maz@kernel.org>
+23
+13
arch/arm64/kvm/emulate-nested.c
+13
arch/arm64/kvm/emulate-nested.c
···
2589
2589
params = esr_sys64_to_params(esr);
2590
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/*
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+
* This implements the pseudocode UnimplementedIDRegister()
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* helper for the purpose of dealing with FEAT_IDST.
2594
+
*/
2595
+
if (in_feat_id_space(¶ms)) {
2596
+
if (kvm_has_feat(vcpu->kvm, ID_AA64MMFR2_EL1, IDS, IMP))
2597
+
kvm_inject_sync(vcpu, kvm_vcpu_get_esr(vcpu));
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+
else
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+
kvm_inject_undefined(vcpu);
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+
2601
+
return true;
2602
+
}
2603
+
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+
/*
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* Check for the IMPDEF range, as per DDI0487 J.a,
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* D18.3.2 Reserved encodings for IMPLEMENTATION
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* DEFINED registers.
+10
arch/arm64/kvm/sys_regs.h
+10
arch/arm64/kvm/sys_regs.h
···
49
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.Op2 = ((esr) >> 17) & 0x7, \
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.is_write = !((esr) & 1) })
51
51
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+
/*
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* The Feature ID space is defined as the System register space in AArch64
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* with op0==3, op1=={0, 1, 3}, CRn==0, CRm=={0-7}, op2=={0-7}.
55
+
*/
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+
static inline bool in_feat_id_space(struct sys_reg_params *p)
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+
{
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return (p->Op0 == 3 && !(p->Op1 & 0b100) && p->Op1 != 2 &&
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+
p->CRn == 0 && !(p->CRm & 0b1000));
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+
}
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+
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struct sys_reg_desc {
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/* Sysreg string for debug */
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const char *name;