Re: [PATCH v3 01/34] KVM: x86: hyper-v: Resurrect dedicated KVM_REQ_HV_TLB_FLUSH flag

Maxim Levitsky
2022-05-11T11:18:45Z

On Thu, 2022-04-14 at 15:19 +0200, Vitaly Kuznetsov wrote:
> In preparation to implementing fine-grained Hyper-V TLB flush and
> L2 TLB flush, resurrect dedicated KVM_REQ_HV_TLB_FLUSH request bit. As
> KVM_REQ_TLB_FLUSH_GUEST is a stronger operation, clear KVM_REQ_HV_TLB_FLUSH
> request in kvm_service_local_tlb_flush_requests() when
> KVM_REQ_TLB_FLUSH_GUEST was also requested.
>
> No functional change intended.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
> ---
> arch/x86/include/asm/kvm_host.h | 2 ++
> arch/x86/kvm/hyperv.c | 4 ++--
> arch/x86/kvm/x86.c | 6 +++++-
> 3 files changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
> index 2c20f715f009..1de3ad9308d8 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -105,6 +105,8 @@
> KVM_ARCH_REQ_FLAGS(30, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
> #define KVM_REQ_MMU_FREE_OBSOLETE_ROOTS \
> KVM_ARCH_REQ_FLAGS(31, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
> +#define KVM_REQ_HV_TLB_FLUSH \
> + KVM_ARCH_REQ_FLAGS(32, KVM_REQUEST_WAIT | KVM_REQUEST_NO_WAKEUP)
>
> #define CR0_RESERVED_BITS \
> (~(unsigned long)(X86_CR0_PE | X86_CR0_MP | X86_CR0_EM | X86_CR0_TS \
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index 46f9dfb60469..b402ad059eb9 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -1876,11 +1876,11 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
> * analyze it here, flush TLB regardless of the specified address space.
> */
> if (all_cpus) {
> - kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH_GUEST);
> + kvm_make_all_cpus_request(kvm, KVM_REQ_HV_TLB_FLUSH);
> } else {
> sparse_set_to_vcpu_mask(kvm, sparse_banks, valid_bank_mask, vcpu_mask);
>
> - kvm_make_vcpus_request_mask(kvm, KVM_REQ_TLB_FLUSH_GUEST, vcpu_mask);
> + kvm_make_vcpus_request_mask(kvm, KVM_REQ_HV_TLB_FLUSH, vcpu_mask);
> }
>
> ret_success:
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> index ab336f7c82e4..f633cff8cd7f 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3360,8 +3360,12 @@ void kvm_service_local_tlb_flush_requests(struct kvm_vcpu *vcpu)
> if (kvm_check_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu))
> kvm_vcpu_flush_tlb_current(vcpu);
>
> - if (kvm_check_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu))
> + if (kvm_check_request(KVM_REQ_TLB_FLUSH_GUEST, vcpu)) {
> kvm_vcpu_flush_tlb_guest(vcpu);
> + kvm_clear_request(KVM_REQ_HV_TLB_FLUSH, vcpu);
> + } else if (kvm_check_request(KVM_REQ_HV_TLB_FLUSH, vcpu)) {
> + kvm_vcpu_flush_tlb_guest(vcpu);
> + }
> }
> EXPORT_SYMBOL_GPL(kvm_service_local_tlb_flush_requests);
>

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>

Best regards,
Maxim Levitsky