linux-kernel - [PATCH RFC 01/19] KVM: x86: hyper-v: Resurrect dedicated KVM_REQ_HV_TLB

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Date:   Mon,  7 Mar 2022 15:50:05 +0100
From:   Vitaly Kuznetsov <vkuznets@...hat.com>
To:     kvm@...r.kernel.org
Cc:     Paolo Bonzini <pbonzini@...hat.com>,
        Sean Christopherson <seanjc@...gle.com>,
        Wanpeng Li <wanpengli@...cent.com>,
        Jim Mattson <jmattson@...gle.com>,
        linux-hyperv@...r.kernel.org,
        Siddharth Chandrasekaran <sidcha@...zon.de>,
        linux-kernel@...r.kernel.org
Subject: [PATCH RFC 01/19] KVM: x86: hyper-v: Resurrect dedicated KVM_REQ_HV_TLB_FLUSH flag

In preparation to implementing fine-grained Hyper-V TLB flush and
Direct 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@...hat.com>
---
 arch/x86/include/asm/kvm_host.h | 2 ++
 arch/x86/kvm/hyperv.c           | 4 ++--
 arch/x86/kvm/x86.c              | 7 ++++++-
 3 files changed, 10 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index da2f3a21e37b..11bcae77bba4 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -104,6 +104,8 @@
 	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 a32f54ab84a2..0cad1fed6007 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1890,11 +1890,11 @@ 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 f79bf4552082..14f539fb9c02 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -3339,7 +3339,12 @@ 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);
+	}
+
+	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);
-- 
2.35.1