Re: [PATCH v8 03/14] KVM: arm64: Use kvm_arch_flush_remote_tlbs()

Gavin Shan
2023-08-09T04:11:18Z

On 8/9/23 09:13, Raghavendra Rao Ananta wrote:
> Stop depending on CONFIG_HAVE_KVM_ARCH_TLB_FLUSH_ALL and opt to
> standardize on kvm_arch_flush_remote_tlbs() since it avoids
> duplicating the generic TLB stats across architectures that implement
> their own remote TLB flush.
>
> This adds an extra function call to the ARM64 kvm_flush_remote_tlbs()
> path, but that is a small cost in comparison to flushing remote TLBs.
>
> In addition, instead of just incrementing remote_tlb_flush_requests
> stat, the generic interface would also increment the
> remote_tlb_flush stat.
>
> Signed-off-by: Raghavendra Rao Ananta <rananta@google.com>
> Reviewed-by: Shaoqin Huang <shahuang@redhat.com>
> ---
> arch/arm64/include/asm/kvm_host.h | 2 ++
> arch/arm64/kvm/Kconfig | 1 -
> arch/arm64/kvm/mmu.c | 6 +++---
> 3 files changed, 5 insertions(+), 4 deletions(-)
>

Reviewed-by: Gavin Shan <gshan@redhat.com>

> diff --git a/arch/arm64/include/asm/kvm_host.h b/arch/arm64/include/asm/kvm_host.h
> index 8b6096753740c..20f2ba149c70c 100644
> --- a/arch/arm64/include/asm/kvm_host.h
> +++ b/arch/arm64/include/asm/kvm_host.h
> @@ -1111,6 +1111,8 @@ int __init kvm_set_ipa_limit(void);
> #define __KVM_HAVE_ARCH_VM_ALLOC
> struct kvm *kvm_arch_alloc_vm(void);
>
> +#define __KVM_HAVE_ARCH_FLUSH_REMOTE_TLBS
> +
> static inline bool kvm_vm_is_protected(struct kvm *kvm)
> {
> return false;
> diff --git a/arch/arm64/kvm/Kconfig b/arch/arm64/kvm/Kconfig
> index f531da6b362e9..6b730fcfee379 100644
> --- a/arch/arm64/kvm/Kconfig
> +++ b/arch/arm64/kvm/Kconfig
> @@ -25,7 +25,6 @@ menuconfig KVM
> select MMU_NOTIFIER
> select PREEMPT_NOTIFIERS
> select HAVE_KVM_CPU_RELAX_INTERCEPT
> - select HAVE_KVM_ARCH_TLB_FLUSH_ALL
> select KVM_MMIO
> select KVM_GENERIC_DIRTYLOG_READ_PROTECT
> select KVM_XFER_TO_GUEST_WORK
> diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c
> index 6db9ef288ec38..0ac721fa27f18 100644
> --- a/arch/arm64/kvm/mmu.c
> +++ b/arch/arm64/kvm/mmu.c
> @@ -161,15 +161,15 @@ static bool memslot_is_logging(struct kvm_memory_slot *memslot)
> }
>
> /**
> - * kvm_flush_remote_tlbs() - flush all VM TLB entries for v7/8
> + * kvm_arch_flush_remote_tlbs() - flush all VM TLB entries for v7/8
> * @kvm: pointer to kvm structure.
> *
> * Interface to HYP function to flush all VM TLB entries
> */
> -void kvm_flush_remote_tlbs(struct kvm *kvm)
> +int kvm_arch_flush_remote_tlbs(struct kvm *kvm)
> {
> - ++kvm->stat.generic.remote_tlb_flush_requests;
> kvm_call_hyp(__kvm_tlb_flush_vmid, &kvm->arch.mmu);
> + return 0;
> }
>
> static bool kvm_is_device_pfn(unsigned long pfn)