Re: [PATCH v2 13/21] arm64: KVM: Implement TLB handling

[Christoffer Dall <christoffer.dall@linaro.org>]

On Fri, Nov 27, 2015 at 06:50:07PM +0000, Marc Zyngier wrote:
> Implement the TLB handling as a direct translation of the assembly
> code version.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
> ---
>  arch/arm64/kvm/hyp/Makefile |  1 +
>  arch/arm64/kvm/hyp/tlb.c    | 72 +++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 73 insertions(+)
>  create mode 100644 arch/arm64/kvm/hyp/tlb.c
> 
> diff --git a/arch/arm64/kvm/hyp/Makefile b/arch/arm64/kvm/hyp/Makefile
> index 56238d0..1a529f5 100644
> --- a/arch/arm64/kvm/hyp/Makefile
> +++ b/arch/arm64/kvm/hyp/Makefile
> @@ -10,3 +10,4 @@ obj-$(CONFIG_KVM_ARM_HOST) += debug-sr.o
>  obj-$(CONFIG_KVM_ARM_HOST) += entry.o
>  obj-$(CONFIG_KVM_ARM_HOST) += switch.o
>  obj-$(CONFIG_KVM_ARM_HOST) += fpsimd.o
> +obj-$(CONFIG_KVM_ARM_HOST) += tlb.o
> diff --git a/arch/arm64/kvm/hyp/tlb.c b/arch/arm64/kvm/hyp/tlb.c
> new file mode 100644
> index 0000000..d4a07d0
> --- /dev/null
> +++ b/arch/arm64/kvm/hyp/tlb.c
> @@ -0,0 +1,72 @@
> +/*
> + * Copyright (C) 2015 - ARM Ltd
> + * Author: Marc Zyngier <marc.zyngier@arm.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2 as
> + * published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program.  If not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "hyp.h"
> +
> +void __hyp_text __tlb_flush_vmid_ipa(struct kvm *kvm, phys_addr_t ipa)
> +{
> +	dsb(ishst);
> +
> +	/* Switch to requested VMID */
> +	kvm = kern_hyp_va(kvm);
> +	write_sysreg(kvm->arch.vttbr, vttbr_el2);
> +	isb();
> +
> +	/*
> +	 * We could do so much better if we had the VA as well.
> +	 * Instead, we invalidate Stage-2 for this IPA, and the
> +	 * whole of Stage-1. Weep...
> +	 */
> +	ipa >>= 12;
> +	asm volatile("tlbi ipas2e1is, %0" : : "r" (ipa));
> +	dsb(ish);

nit: missing white space

> +	/*
> +	 * We have to ensure completion of the invalidation at Stage-2,
> +	 * since a table walk on another CPU could refill a TLB with a
> +	 * complete (S1 + S2) walk based on the old Stage-2 mapping if
> +	 * the Stage-1 invalidation happened first.
> +	 */

nit: isn't that comment targeting the dsb(ish) above as in the asm code
and should be moved above that line?

> +	asm volatile("tlbi vmalle1is" : : );
> +	dsb(ish);
> +	isb();
> +
> +	write_sysreg(0, vttbr_el2);
> +}
> +
> +void __hyp_text __tlb_flush_vmid(struct kvm *kvm)
> +{
> +	dsb(ishst);
> +
> +	/* Switch to requested VMID */
> +	kvm = kern_hyp_va(kvm);
> +	write_sysreg(kvm->arch.vttbr, vttbr_el2);
> +	isb();
> +
> +	asm volatile("tlbi vmalls12e1is" : : );
> +	dsb(ish);
> +	isb();
> +
> +	write_sysreg(0, vttbr_el2);
> +}
> +
> +void __hyp_text __tlb_flush_vm_context(void)
> +{
> +	dsb(ishst);
> +	asm volatile("tlbi alle1is	\n"
> +		     "ic ialluis	  ": : );
> +	dsb(ish);
> +}
> -- 
> 2.1.4
> 

Otherwise:

Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>