KVM: arm64: nv: Forward FP/ASIMD traps to guest hypervisor

Give precedence to the guest hypervisor's trap configuration when
routing an FP/ASIMD trap taken to EL2. Take advantage of the
infrastructure for translating CPTR_EL2 into the VHE (i.e. EL1) format
and base the trap decision solely on the VHE view of the register. The
in-memory value of CPTR_EL2 will always be up to date for the guest
hypervisor (more on that later), so just read it directly from memory.

Bury all of this behind a macro keyed off of the CPTR bitfield in
anticipation of supporting other traps (e.g. SVE).

[maz: account for HCR_EL2.E2H when testing for TFP/FPEN, with
 all the hard work actually being done by Chase Conklin]
[ oliver: translate nVHE->VHE format for testing traps; macro for reuse
 in other CPTR_EL2.xEN fields ]

Signed-off-by: Jintack Lim <jintack.lim@linaro.org>
Signed-off-by: Christoffer Dall <christoffer.dall@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
Reviewed-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20240620164653.1130714-2-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
This commit is contained in:
Jintack Lim
2024-06-20 16:46:38 +00:00
committed by Oliver Upton
parent 83a7eefedc
commit d2b2ecba8d
3 changed files with 58 additions and 4 deletions

View File

@@ -94,11 +94,19 @@ static int handle_smc(struct kvm_vcpu *vcpu)
}
/*
* Guest access to FP/ASIMD registers are routed to this handler only
* when the system doesn't support FP/ASIMD.
* This handles the cases where the system does not support FP/ASIMD or when
* we are running nested virtualization and the guest hypervisor is trapping
* FP/ASIMD accesses by its guest guest.
*
* All other handling of guest vs. host FP/ASIMD register state is handled in
* fixup_guest_exit().
*/
static int handle_no_fpsimd(struct kvm_vcpu *vcpu)
static int kvm_handle_fpasimd(struct kvm_vcpu *vcpu)
{
if (guest_hyp_fpsimd_traps_enabled(vcpu))
return kvm_inject_nested_sync(vcpu, kvm_vcpu_get_esr(vcpu));
/* This is the case when the system doesn't support FP/ASIMD. */
kvm_inject_undefined(vcpu);
return 1;
}
@@ -304,7 +312,7 @@ static exit_handle_fn arm_exit_handlers[] = {
[ESR_ELx_EC_BREAKPT_LOW]= kvm_handle_guest_debug,
[ESR_ELx_EC_BKPT32] = kvm_handle_guest_debug,
[ESR_ELx_EC_BRK64] = kvm_handle_guest_debug,
[ESR_ELx_EC_FP_ASIMD] = handle_no_fpsimd,
[ESR_ELx_EC_FP_ASIMD] = kvm_handle_fpasimd,
[ESR_ELx_EC_PAC] = kvm_handle_ptrauth,
};