From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: Sean Christopherson <seanjc@google.com>
Cc: Wanpeng Li <wanpengli@tencent.com>,
Jim Mattson <jmattson@google.com>, Joerg Roedel <joro@8bytes.org>,
kvm@vger.kernel.org, linux-hyperv@vger.kernel.org,
linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org,
Ajay Garg <ajaygargnsit@gmail.com>,
Paolo Bonzini <pbonzini@redhat.com>,
"K. Y. Srinivasan" <kys@microsoft.com>,
Haiyang Zhang <haiyangz@microsoft.com>,
Stephen Hemminger <sthemmin@microsoft.com>,
Wei Liu <wei.liu@kernel.org>, Dexuan Cui <decui@microsoft.com>,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH v2 3/8] KVM: x86: Refactor kvm_hv_flush_tlb() to reduce indentation
Date: Mon, 01 Nov 2021 11:00:25 +0100 [thread overview]
Message-ID: <877ddskxfq.fsf@vitty.brq.redhat.com> (raw)
In-Reply-To: <20211030000800.3065132-4-seanjc@google.com>
Sean Christopherson <seanjc@google.com> writes:
> Refactor the "extended" path of kvm_hv_flush_tlb() to reduce the nesting
> depth for the non-fast sparse path, and to make the code more similar to
> the extended path in kvm_hv_send_ipi().
>
> No functional change intended.
>
> Signed-off-by: Sean Christopherson <seanjc@google.com>
> ---
> arch/x86/kvm/hyperv.c | 40 +++++++++++++++++++++-------------------
> 1 file changed, 21 insertions(+), 19 deletions(-)
>
> diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
> index cf18aa1712bf..e68931ed27f6 100644
> --- a/arch/x86/kvm/hyperv.c
> +++ b/arch/x86/kvm/hyperv.c
> @@ -1814,31 +1814,33 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool
> if (hc->var_cnt != bitmap_weight((unsigned long *)&valid_bank_mask, 64))
> return HV_STATUS_INVALID_HYPERCALL_INPUT;
>
> - if (!hc->var_cnt && !all_cpus)
> + if (all_cpus)
> + goto do_flush;
You could've probably done:
if (all_cpus) {
kvm_make_all_cpus_request(kvm, KVM_REQ_TLB_FLUSH_GUEST);
goto ret_success;
}
to get rid on the second 'all_cpus' check (and maybe even 'do_flush'
label with some extra work) below.
> +
> + if (!hc->var_cnt)
> goto ret_success;
>
> - if (!all_cpus) {
> - if (hc->fast) {
> - if (hc->var_cnt > HV_HYPERCALL_MAX_XMM_REGISTERS - 1)
> - return HV_STATUS_INVALID_HYPERCALL_INPUT;
> - for (i = 0; i < hc->var_cnt; i += 2) {
> - sparse_banks[i] = sse128_lo(hc->xmm[i / 2 + 1]);
> - sparse_banks[i + 1] = sse128_hi(hc->xmm[i / 2 + 1]);
> - }
> - } else {
> - if (hc->var_cnt > 64)
> - return HV_STATUS_INVALID_HYPERCALL_INPUT;
> -
> - gpa = hc->ingpa + offsetof(struct hv_tlb_flush_ex,
> - hv_vp_set.bank_contents);
> - if (unlikely(kvm_read_guest(kvm, gpa, sparse_banks,
> - hc->var_cnt *
> - sizeof(sparse_banks[0]))))
> - return HV_STATUS_INVALID_HYPERCALL_INPUT;
> + if (hc->fast) {
> + if (hc->var_cnt > HV_HYPERCALL_MAX_XMM_REGISTERS - 1)
> + return HV_STATUS_INVALID_HYPERCALL_INPUT;
> + for (i = 0; i < hc->var_cnt; i += 2) {
> + sparse_banks[i] = sse128_lo(hc->xmm[i / 2 + 1]);
> + sparse_banks[i + 1] = sse128_hi(hc->xmm[i / 2 + 1]);
> }
> + goto do_flush;
> }
> +
> + if (hc->var_cnt > 64)
> + return HV_STATUS_INVALID_HYPERCALL_INPUT;
> +
> + gpa = hc->ingpa + offsetof(struct hv_tlb_flush_ex,
> + hv_vp_set.bank_contents);
> + if (unlikely(kvm_read_guest(kvm, gpa, sparse_banks,
> + hc->var_cnt * sizeof(sparse_banks[0]))))
> + return HV_STATUS_INVALID_HYPERCALL_INPUT;
> }
>
> +do_flush:
> /*
> * vcpu->arch.cr3 may not be up-to-date for running vCPUs so we can't
> * analyze it here, flush TLB regardless of the specified address space.
Reviewed-by: Vitaly Kuznetsov <vkuznets@redhat.com>
--
Vitaly
next prev parent reply other threads:[~2021-11-01 10:01 UTC|newest]
Thread overview: 22+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-30 0:07 [PATCH v2 0/8] KVM: x86: Hyper-V hypercall fix and cleanups Sean Christopherson
2021-10-30 0:07 ` [PATCH v2 1/8] KVM: x86: Ignore sparse banks size for an "all CPUs", non-sparse IPI req Sean Christopherson
2021-11-01 9:05 ` Vitaly Kuznetsov
2021-10-30 0:07 ` [PATCH v2 2/8] KVM: x86: Get the number of Hyper-V sparse banks from the VARHEAD field Sean Christopherson
2021-11-01 9:52 ` Vitaly Kuznetsov
2021-10-30 0:07 ` [PATCH v2 3/8] KVM: x86: Refactor kvm_hv_flush_tlb() to reduce indentation Sean Christopherson
2021-11-01 10:00 ` Vitaly Kuznetsov [this message]
2021-12-03 23:45 ` Sean Christopherson
2021-10-30 0:07 ` [PATCH v2 4/8] KVM: x86: Add a helper to get the sparse VP_SET for IPIs and TLB flushes Sean Christopherson
2021-11-01 10:06 ` Vitaly Kuznetsov
2021-10-30 0:07 ` [PATCH v2 5/8] KVM: x86: Don't bother reading sparse banks that end up being ignored Sean Christopherson
2021-11-01 9:46 ` Vitaly Kuznetsov
2021-10-30 0:07 ` [PATCH v2 6/8] KVM: x86: Shove vp_bitmap handling down into sparse_set_to_vcpu_mask() Sean Christopherson
2021-11-01 10:12 ` Vitaly Kuznetsov
2021-10-30 0:07 ` [PATCH v2 7/8] KVM: x86: Reject fixeds-size Hyper-V hypercalls with non-zero "var_cnt" Sean Christopherson
2021-11-01 10:27 ` Vitaly Kuznetsov
2021-12-03 23:48 ` Sean Christopherson
2021-10-30 0:08 ` [PATCH v2 8/8] KVM: x86: Add checks for reserved-to-zero Hyper-V hypercall fields Sean Christopherson
2021-11-01 10:33 ` Vitaly Kuznetsov
2021-12-02 2:13 ` Sean Christopherson
2021-12-02 15:16 ` Michael Kelley (LINUX)
2021-12-03 14:09 ` ** POTENTIAL FRAUD ALERT - RED HAT ** " Vitaly Kuznetsov
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