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KVM: arm64: nv: Handle CPACR_EL1 traps

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Handle CPACR_EL1 accesses when running a VHE guest. In order to
limit the cost of the emulation, implement it ass a shallow exit.

In the other cases:

- this is a nVHE L1 which will write to memory, and we don't trap

- this is a L2 guest:

  * the L1 has CPTR_EL2.TCPAC==0, and the L2 has direct register
   access

  * the L1 has CPTR_EL2.TCPAC==1, and the L2 will trap, but the
    handling is defered to the general handling for forwarding

Signed-off-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-10-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Marc Zyngier
2024-06-20 16:46:46 +00:00
committed by Oliver Upton
parent 1785f020b1
commit 493da2b1c4
1 changed files with 31 additions and 1 deletions
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32
arch/arm64/kvm/hyp/vhe/switch.c
View File

@@ -266,10 +266,40 @@ static void kvm_hyp_save_fpsimd_host(struct kvm_vcpu *vcpu)
__fpsimd_save_state(*host_data_ptr(fpsimd_state));
}
static bool kvm_hyp_handle_cpacr_el1(struct kvm_vcpu *vcpu, u64 *exit_code)
{
u64 esr = kvm_vcpu_get_esr(vcpu);
int rt;
if (!is_hyp_ctxt(vcpu) || esr_sys64_to_sysreg(esr) != SYS_CPACR_EL1)
return false;
rt = kvm_vcpu_sys_get_rt(vcpu);
if ((esr & ESR_ELx_SYS64_ISS_DIR_MASK) == ESR_ELx_SYS64_ISS_DIR_READ) {
vcpu_set_reg(vcpu, rt, __vcpu_sys_reg(vcpu, CPTR_EL2));
} else {
vcpu_write_sys_reg(vcpu, vcpu_get_reg(vcpu, rt), CPTR_EL2);
__activate_cptr_traps(vcpu);
}
__kvm_skip_instr(vcpu);
return true;
}
static bool kvm_hyp_handle_sysreg_vhe(struct kvm_vcpu *vcpu, u64 *exit_code)
{
if (kvm_hyp_handle_cpacr_el1(vcpu, exit_code))
return true;
return kvm_hyp_handle_sysreg(vcpu, exit_code);
}
static const exit_handler_fn hyp_exit_handlers[] = {
[0 ... ESR_ELx_EC_MAX] = NULL,
[ESR_ELx_EC_CP15_32] = kvm_hyp_handle_cp15_32,
[ESR_ELx_EC_SYS64] = kvm_hyp_handle_sysreg,
[ESR_ELx_EC_SYS64] = kvm_hyp_handle_sysreg_vhe,
[ESR_ELx_EC_SVE] = kvm_hyp_handle_fpsimd,
[ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd,
[ESR_ELx_EC_IABT_LOW] = kvm_hyp_handle_iabt_low,