Re: [PATCH v6 02/38] KVM: x86: hyper-v: Resurrect dedicated KVM_REQ_HV_TLB_FLUSH flag
From: Maxim Levitsky
Date: Tue Jun 07 2022 - 04:47:17 EST
On Mon, 2022-06-06 at 10:36 +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/KVM_REQ_TLB_FLUSH_CURRENT are stronger
> operations,
> clear KVM_REQ_HV_TLB_FLUSH request in
> kvm_service_local_tlb_flush_requests()
> when any of these were also requested.
>
> No (real) functional change intended.
>
> Signed-off-by: Vitaly Kuznetsov <vkuznets@xxxxxxxxxx>
> ---
> arch/x86/include/asm/kvm_host.h | 2 ++
> arch/x86/kvm/hyperv.c | 4 ++--
> arch/x86/kvm/x86.c | 10 ++++++++--
> 3 files changed, 12 insertions(+), 4 deletions(-)
>
> diff --git a/arch/x86/include/asm/kvm_host.h
> b/arch/x86/include/asm/kvm_host.h
> index 8699f715d867..7a6a6f47b603 100644
> --- a/arch/x86/include/asm/kvm_host.h
> +++ b/arch/x86/include/asm/kvm_host.h
> @@ -108,6 +108,8 @@
> 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 67732e658e76..80cd3eb5e7de 100644
> --- a/arch/x86/kvm/x86.c
> +++ b/arch/x86/kvm/x86.c
> @@ -3353,11 +3353,17 @@ static inline void
> kvm_vcpu_flush_tlb_current(struct kvm_vcpu *vcpu)
> */
> void kvm_service_local_tlb_flush_requests(struct kvm_vcpu *vcpu)
> {
> - if (kvm_check_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu))
> + if (kvm_check_request(KVM_REQ_TLB_FLUSH_CURRENT, vcpu)) {
> kvm_vcpu_flush_tlb_current(vcpu);
> + kvm_clear_request(KVM_REQ_HV_TLB_FLUSH, 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@xxxxxxxxxx>
Best regards,
Maxim Levitsky