linux-kernel - [PATCH RFC 09/19] KVM: nVMX: Keep track of hv_vm_id/hv_vp

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Date:   Mon,  7 Mar 2022 15:50:13 +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 09/19] KVM: nVMX: Keep track of hv_vm_id/hv_vp_id when eVMCS is in use

To handle Direct TLB flush requests from L2, KVM needs to keep track
of L2's VM_ID/VP_IDs which are set by L1 hypervisor. 'Partition assist
page' address is also needed to handle post-flush exit to L1 (upon
request).

Assume vm_id/vp_id/partition_assist_page don't change while eVMCS
is active.

Signed-off-by: Vitaly Kuznetsov <vkuznets@...hat.com>
---
 arch/x86/include/asm/kvm_host.h |  6 ++++++
 arch/x86/kvm/vmx/nested.c       | 24 ++++++++++++++++++++----
 2 files changed, 26 insertions(+), 4 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 1fce8232a2e9..21b502aa9655 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -618,6 +618,12 @@ struct kvm_vcpu_hv {
 
 	/* Preallocated buffer for handling hypercalls passing sparse vCPU set */
 	u64 sparse_banks[64];
+
+	struct {
+		u64 pa_page_gpa;
+		u64 vm_id;
+		u32 vp_id;
+	} nested;
 };
 
 /* Xen HVM per vcpu emulation context */
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index f18744f7ff82..dd3054c3291c 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -225,6 +225,7 @@ static void vmx_disable_shadow_vmcs(struct vcpu_vmx *vmx)
 
 static inline void nested_release_evmcs(struct kvm_vcpu *vcpu)
 {
+	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
 	if (evmptr_is_valid(vmx->nested.hv_evmcs_vmptr)) {
@@ -233,6 +234,9 @@ static inline void nested_release_evmcs(struct kvm_vcpu *vcpu)
 	}
 
 	vmx->nested.hv_evmcs_vmptr = EVMPTR_INVALID;
+	hv_vcpu->nested.pa_page_gpa = INVALID_GPA;
+	hv_vcpu->nested.vm_id = 0;
+	hv_vcpu->nested.vp_id = 0;
 }
 
 static void vmx_sync_vmcs_host_state(struct vcpu_vmx *vmx,
@@ -2042,15 +2046,27 @@ static enum nested_evmptrld_status nested_vmx_handle_enlightened_vmptrld(
 
 	}
 
-	/*
-	 * Clean fields data can't be used on VMLAUNCH and when we switch
-	 * between different L2 guests as KVM keeps a single VMCS12 per L1.
-	 */
 	if (from_launch || evmcs_gpa_changed) {
+		struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(&vmx->vcpu);
+		struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs;
+
+		/*
+		 * Clean fields data can't be used on VMLAUNCH and when we
+		 * switch between different L2 guests as KVM keeps a single
+		 * VMCS12 per L1.
+		 */
 		vmx->nested.hv_evmcs->hv_clean_fields &=
 			~HV_VMX_ENLIGHTENED_CLEAN_FIELD_ALL;
 
 		vmx->nested.force_msr_bitmap_recalc = true;
+
+		/*
+		 * Assume vm_id/vp_id/partition_assist_page don't change while
+		 * eVMCS is active.
+		 */
+		hv_vcpu->nested.pa_page_gpa = evmcs->partition_assist_page;
+		hv_vcpu->nested.vm_id = evmcs->hv_vm_id;
+		hv_vcpu->nested.vp_id = evmcs->hv_vp_id;
 	}
 
 	return EVMPTRLD_SUCCEEDED;
-- 
2.35.1