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SubjectRe: [PATCH 1/2] KVM: arm64: pkvm: Drop unnecessary FP/SIMD trap handler
Hi Oliver,

On Mon, May 9, 2022 at 5:26 PM Oliver Upton <oupton@google.com> wrote:
>
> The pVM-specific FP/SIMD trap handler just calls straight into the
> generic trap handler. Avoid the indirection and just call the hyp
> handler directly.
>
> Note that the BUILD_BUG_ON() pattern is repeated in
> pvm_init_traps_aa64pfr0(), which is likely a better home for it.
>
> No functional change intended.

Reviewed-by: Fuad Tabba <tabba@google.com>

Cheers,
/fuad

>
> Signed-off-by: Oliver Upton <oupton@google.com>
> ---
> arch/arm64/kvm/hyp/nvhe/switch.c | 19 +------------------
> 1 file changed, 1 insertion(+), 18 deletions(-)
>
> diff --git a/arch/arm64/kvm/hyp/nvhe/switch.c b/arch/arm64/kvm/hyp/nvhe/switch.c
> index 6410d21d8695..3dee2ad96e10 100644
> --- a/arch/arm64/kvm/hyp/nvhe/switch.c
> +++ b/arch/arm64/kvm/hyp/nvhe/switch.c
> @@ -175,23 +175,6 @@ static bool kvm_handle_pvm_sys64(struct kvm_vcpu *vcpu, u64 *exit_code)
> kvm_handle_pvm_sysreg(vcpu, exit_code));
> }
>
> -/**
> - * Handler for protected floating-point and Advanced SIMD accesses.
> - *
> - * Returns true if the hypervisor has handled the exit, and control should go
> - * back to the guest, or false if it hasn't.
> - */
> -static bool kvm_handle_pvm_fpsimd(struct kvm_vcpu *vcpu, u64 *exit_code)
> -{
> - /* Linux guests assume support for floating-point and Advanced SIMD. */
> - BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_FP),
> - PVM_ID_AA64PFR0_ALLOW));
> - BUILD_BUG_ON(!FIELD_GET(ARM64_FEATURE_MASK(ID_AA64PFR0_ASIMD),
> - PVM_ID_AA64PFR0_ALLOW));
> -
> - return kvm_hyp_handle_fpsimd(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,
> @@ -207,7 +190,7 @@ static const exit_handler_fn pvm_exit_handlers[] = {
> [0 ... ESR_ELx_EC_MAX] = NULL,
> [ESR_ELx_EC_SYS64] = kvm_handle_pvm_sys64,
> [ESR_ELx_EC_SVE] = kvm_handle_pvm_restricted,
> - [ESR_ELx_EC_FP_ASIMD] = kvm_handle_pvm_fpsimd,
> + [ESR_ELx_EC_FP_ASIMD] = kvm_hyp_handle_fpsimd,
> [ESR_ELx_EC_IABT_LOW] = kvm_hyp_handle_iabt_low,
> [ESR_ELx_EC_DABT_LOW] = kvm_hyp_handle_dabt_low,
> [ESR_ELx_EC_PAC] = kvm_hyp_handle_ptrauth,
> --
> 2.36.0.512.ge40c2bad7a-goog
>

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