linux-kernel - [PATCH v3 3/8] KVM: x86: Refactor kvm_hv_flush

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Date:   Tue,  7 Dec 2021 22:09:21 +0000
From:   Sean Christopherson <seanjc@...gle.com>
To:     Paolo Bonzini <pbonzini@...hat.com>,
        "K. Y. Srinivasan" <kys@...rosoft.com>,
        Haiyang Zhang <haiyangz@...rosoft.com>,
        Stephen Hemminger <sthemmin@...rosoft.com>,
        Wei Liu <wei.liu@...nel.org>, Dexuan Cui <decui@...rosoft.com>,
        Arnd Bergmann <arnd@...db.de>
Cc:     Sean Christopherson <seanjc@...gle.com>,
        Vitaly Kuznetsov <vkuznets@...hat.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        Joerg Roedel <joro@...tes.org>, kvm@...r.kernel.org,
        linux-hyperv@...r.kernel.org, linux-arch@...r.kernel.org,
        linux-kernel@...r.kernel.org, Ajay Garg <ajaygargnsit@...il.com>
Subject: [PATCH v3 3/8] KVM: x86: Refactor kvm_hv_flush_tlb() to reduce indentation

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@...gle.com>
Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.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 d8a7b63f676f..9bc856370a2d 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1815,31 +1815,33 @@ 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;
+
+		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.
-- 
2.34.1.400.ga245620fadb-goog