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KVM: arm64: Spin off helper for programming CPTR traps

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A subsequent change to KVM will add preliminary support for merging a
guest hypervisor's CPTR traps with that of KVM. Prepare by spinning off
a new helper for managing CPTR traps.

Avoid reading CPACR_EL1 for the baseline trap config, and start off with
the most restrictive set of traps that is subsequently relaxed.

Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-9-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Oliver Upton 2024-06-20 16:46:45 +00:00
parent 2e3cf82063
commit 1785f020b1
1 changed files with 24 additions and 24 deletions
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48
arch/arm64/kvm/hyp/vhe/switch.c
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@ -65,6 +65,29 @@ static u64 __compute_hcr(struct kvm_vcpu *vcpu)
return hcr | (__vcpu_sys_reg(vcpu, HCR_EL2) & ~NV_HCR_GUEST_EXCLUDE);
}
static void __activate_cptr_traps(struct kvm_vcpu *vcpu)
{
/*
* With VHE (HCR.E2H == 1), accesses to CPACR_EL1 are routed to
* CPTR_EL2. In general, CPACR_EL1 has the same layout as CPTR_EL2,
* except for some missing controls, such as TAM.
* In this case, CPTR_EL2.TAM has the same position with or without
* VHE (HCR.E2H == 1) which allows us to use here the CPTR_EL2.TAM
* shift value for trapping the AMU accesses.
*/
u64 val = CPACR_ELx_TTA | CPTR_EL2_TAM;
if (guest_owns_fp_regs()) {
val |= CPACR_ELx_FPEN;
if (vcpu_has_sve(vcpu))
val |= CPACR_ELx_ZEN;
} else {
__activate_traps_fpsimd32(vcpu);
}
write_sysreg(val, cpacr_el1);
}
static void __activate_traps(struct kvm_vcpu *vcpu)
{
u64 val;
@ -91,30 +114,7 @@ static void __activate_traps(struct kvm_vcpu *vcpu)
}
}
val = read_sysreg(cpacr_el1);
val |= CPACR_ELx_TTA;
val &= ~(CPACR_ELx_ZEN | CPACR_ELx_SMEN);
/*
* With VHE (HCR.E2H == 1), accesses to CPACR_EL1 are routed to
* CPTR_EL2. In general, CPACR_EL1 has the same layout as CPTR_EL2,
* except for some missing controls, such as TAM.
* In this case, CPTR_EL2.TAM has the same position with or without
* VHE (HCR.E2H == 1) which allows us to use here the CPTR_EL2.TAM
* shift value for trapping the AMU accesses.
*/
val |= CPTR_EL2_TAM;
if (guest_owns_fp_regs()) {
if (vcpu_has_sve(vcpu))
val |= CPACR_ELx_ZEN;
} else {
val &= ~CPACR_ELx_FPEN;
__activate_traps_fpsimd32(vcpu);
}
write_sysreg(val, cpacr_el1);
__activate_cptr_traps(vcpu);
write_sysreg(__this_cpu_read(kvm_hyp_vector), vbar_el1);
}