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From: Vitaly Kuznetsov <vkuznets@redhat.com>
To: kvm@vger.kernel.org, Paolo Bonzini <pbonzini@redhat.com>
Cc: Sean Christopherson <seanjc@google.com>,
	Wanpeng Li <wanpengli@tencent.com>,
	Jim Mattson <jmattson@google.com>,
	Michael Kelley <mikelley@microsoft.com>,
	Siddharth Chandrasekaran <sidcha@amazon.de>,
	Yuan Yao <yuan.yao@linux.intel.com>,
	Maxim Levitsky <mlevitsk@redhat.com>,
	linux-hyperv@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH v10 20/39] KVM: nVMX: hyper-v: Enable L2 TLB flush
Date: Wed, 21 Sep 2022 17:24:17 +0200	[thread overview]
Message-ID: <20220921152436.3673454-21-vkuznets@redhat.com> (raw)
In-Reply-To: <20220921152436.3673454-1-vkuznets@redhat.com>

Enable L2 TLB flush feature on nVMX when:
- Enlightened VMCS is in use.
- The feature flag is enabled in eVMCS.
- The feature flag is enabled in partition assist page.

Perform synthetic vmexit to L1 after processing TLB flush call upon
request (HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH).

Note: nested_evmcs_l2_tlb_flush_enabled() uses cached VP assist page copy
which gets updated from nested_vmx_handle_enlightened_vmptrld(). This is
also guaranteed to happen post migration with eVMCS backed L2 running.

Reviewed-by: Maxim Levitsky <mlevitsk@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 arch/x86/kvm/vmx/evmcs.c  | 17 +++++++++++++++++
 arch/x86/kvm/vmx/evmcs.h  | 10 ++++++++++
 arch/x86/kvm/vmx/nested.c | 22 ++++++++++++++++++++++
 3 files changed, 49 insertions(+)

diff --git a/arch/x86/kvm/vmx/evmcs.c b/arch/x86/kvm/vmx/evmcs.c
index 635a0c81ff1d..f7fedc3ed247 100644
--- a/arch/x86/kvm/vmx/evmcs.c
+++ b/arch/x86/kvm/vmx/evmcs.c
@@ -6,6 +6,7 @@
 #include "../hyperv.h"
 #include "../cpuid.h"
 #include "evmcs.h"
+#include "nested.h"
 #include "vmcs.h"
 #include "vmx.h"
 #include "trace.h"
@@ -501,6 +502,22 @@ int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 	return 0;
 }
 
+bool nested_evmcs_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu)
+{
+	struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
+	struct vcpu_vmx *vmx = to_vmx(vcpu);
+	struct hv_enlightened_vmcs *evmcs = vmx->nested.hv_evmcs;
+
+	if (!hv_vcpu || !evmcs)
+		return false;
+
+	if (!evmcs->hv_enlightenments_control.nested_flush_hypercall)
+		return false;
+
+	return hv_vcpu->vp_assist_page.nested_control.features.directhypercall;
+}
+
 void vmx_hv_inject_synthetic_vmexit_post_tlb_flush(struct kvm_vcpu *vcpu)
 {
+	nested_vmx_vmexit(vcpu, HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH, 0, 0);
 }
diff --git a/arch/x86/kvm/vmx/evmcs.h b/arch/x86/kvm/vmx/evmcs.h
index 7ad56fbc4b4d..dd1589336e79 100644
--- a/arch/x86/kvm/vmx/evmcs.h
+++ b/arch/x86/kvm/vmx/evmcs.h
@@ -63,6 +63,15 @@ DECLARE_STATIC_KEY_FALSE(enable_evmcs);
 #define EVMCS1_UNSUPPORTED_VMENTRY_CTRL (0)
 #define EVMCS1_UNSUPPORTED_VMFUNC (VMX_VMFUNC_EPTP_SWITCHING)
 
+/*
+ * Note, Hyper-V isn't actually stealing bit 28 from Intel, just abusing it by
+ * pairing it with architecturally impossible exit reasons.  Bit 28 is set only
+ * on SMI exits to a SMI transfer monitor (STM) and if and only if a MTF VM-Exit
+ * is pending.  I.e. it will never be set by hardware for non-SMI exits (there
+ * are only three), nor will it ever be set unless the VMM is an STM.
+ */
+#define HV_VMX_SYNTHETIC_EXIT_REASON_TRAP_AFTER_FLUSH 0x10000031
+
 struct evmcs_field {
 	u16 offset;
 	u16 clean_field;
@@ -241,6 +250,7 @@ int nested_enable_evmcs(struct kvm_vcpu *vcpu,
 			uint16_t *vmcs_version);
 void nested_evmcs_filter_control_msr(struct kvm_vcpu *vcpu, u32 msr_index, u64 *pdata);
 int nested_evmcs_check_controls(struct vmcs12 *vmcs12);
+bool nested_evmcs_l2_tlb_flush_enabled(struct kvm_vcpu *vcpu);
 void vmx_hv_inject_synthetic_vmexit_post_tlb_flush(struct kvm_vcpu *vcpu);
 
 #endif /* __KVM_X86_VMX_EVMCS_H */
diff --git a/arch/x86/kvm/vmx/nested.c b/arch/x86/kvm/vmx/nested.c
index 0634518a6719..1451a7a2c488 100644
--- a/arch/x86/kvm/vmx/nested.c
+++ b/arch/x86/kvm/vmx/nested.c
@@ -1132,6 +1132,17 @@ static void nested_vmx_transition_tlb_flush(struct kvm_vcpu *vcpu,
 {
 	struct vcpu_vmx *vmx = to_vmx(vcpu);
 
+	/*
+	 * KVM_REQ_HV_TLB_FLUSH flushes entries from either L1's VP_ID or
+	 * L2's VP_ID upon request from the guest. Make sure we check for
+	 * pending entries for the case when the request got misplaced (e.g.
+	 * a transition from L2->L1 happened while processing L2 TLB flush
+	 * request or vice versa). kvm_hv_vcpu_flush_tlb() will not flush
+	 * anything if there are no requests in the corresponding buffer.
+	 */
+	if (to_hv_vcpu(vcpu))
+		kvm_make_request(KVM_REQ_HV_TLB_FLUSH, vcpu);
+
 	/*
 	 * If vmcs12 doesn't use VPID, L1 expects linear and combined mappings
 	 * for *all* contexts to be flushed on VM-Enter/VM-Exit, i.e. it's a
@@ -3267,6 +3278,12 @@ static bool nested_get_vmcs12_pages(struct kvm_vcpu *vcpu)
 
 static bool vmx_get_nested_state_pages(struct kvm_vcpu *vcpu)
 {
+	/*
+	 * Note: nested_get_evmcs_page() also updates 'vp_assist_page' copy
+	 * in 'struct kvm_vcpu_hv' in case eVMCS is in use, this is mandatory
+	 * to make nested_evmcs_l2_tlb_flush_enabled() work correctly post
+	 * migration.
+	 */
 	if (!nested_get_evmcs_page(vcpu)) {
 		pr_debug_ratelimited("%s: enlightened vmptrld failed\n",
 				     __func__);
@@ -6143,6 +6160,11 @@ static bool nested_vmx_l0_wants_exit(struct kvm_vcpu *vcpu,
 		 * Handle L2's bus locks in L0 directly.
 		 */
 		return true;
+	case EXIT_REASON_VMCALL:
+		/* Hyper-V L2 TLB flush hypercall is handled by L0 */
+		return guest_hv_cpuid_has_l2_tlb_flush(vcpu) &&
+			nested_evmcs_l2_tlb_flush_enabled(vcpu) &&
+			kvm_hv_is_tlb_flush_hcall(vcpu);
 	default:
 		break;
 	}
-- 
2.37.3


  parent reply	other threads:[~2022-09-21 15:27 UTC|newest]

Thread overview: 64+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-21 15:23 [PATCH v10 00/39] KVM: x86: hyper-v: Fine-grained TLB flush + L2 TLB flush features Vitaly Kuznetsov
2022-09-21 15:23 ` [PATCH v10 01/39] KVM: x86: Rename 'enable_direct_tlbflush' to 'enable_l2_tlb_flush' Vitaly Kuznetsov
2022-09-21 15:23 ` [PATCH v10 02/39] KVM: x86: hyper-v: Resurrect dedicated KVM_REQ_HV_TLB_FLUSH flag Vitaly Kuznetsov
2022-09-21 16:23   ` Sean Christopherson
2022-09-21 16:45     ` Sean Christopherson
2022-09-22  9:35       ` Vitaly Kuznetsov
2022-09-22  9:31     ` Vitaly Kuznetsov
2022-09-22 15:23       ` Sean Christopherson
2022-09-22 15:37         ` Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 03/39] KVM: x86: hyper-v: Introduce TLB flush fifo Vitaly Kuznetsov
2022-09-21 16:56   ` Sean Christopherson
2022-09-22  9:42     ` Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 04/39] KVM: x86: hyper-v: Add helper to read hypercall data for array Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 05/39] KVM: x86: hyper-v: Handle HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST{,EX} calls gently Vitaly Kuznetsov
2022-09-21 17:00   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 06/39] KVM: x86: hyper-v: Expose support for extended gva ranges for flush hypercalls Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 07/39] KVM: x86: Prepare kvm_hv_flush_tlb() to handle L2's GPAs Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 08/39] x86/hyperv: Introduce HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE_BANK constants Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 09/39] KVM: x86: hyper-v: Use HV_MAX_SPARSE_VCPU_BANKS/HV_VCPUS_PER_SPARSE_BANK instead of raw '64' Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 10/39] KVM: x86: hyper-v: Don't use sparse_set_to_vcpu_mask() in kvm_hv_send_ipi() Vitaly Kuznetsov
2022-09-21 20:54   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 11/39] KVM: x86: hyper-v: Create a separate fifo for L2 TLB flush Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 12/39] KVM: x86: hyper-v: Use preallocated buffer in 'struct kvm_vcpu_hv' instead of on-stack 'sparse_banks' Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 13/39] KVM: nVMX: Keep track of hv_vm_id/hv_vp_id when eVMCS is in use Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 14/39] KVM: nSVM: Keep track of Hyper-V hv_vm_id/hv_vp_id Vitaly Kuznetsov
2022-09-21 21:16   ` Sean Christopherson
2022-09-22  9:51     ` Vitaly Kuznetsov
2022-09-22 19:52       ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 15/39] KVM: x86: Introduce .hv_inject_synthetic_vmexit_post_tlb_flush() nested hook Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 16/39] KVM: x86: hyper-v: Introduce kvm_hv_is_tlb_flush_hcall() Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 17/39] KVM: x86: hyper-v: L2 TLB flush Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 18/39] KVM: x86: hyper-v: Introduce fast guest_hv_cpuid_has_l2_tlb_flush() check Vitaly Kuznetsov
2022-09-21 21:19   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 19/39] KVM: nVMX: hyper-v: Cache VP assist page in 'struct kvm_vcpu_hv' Vitaly Kuznetsov
2022-09-21 15:24 ` Vitaly Kuznetsov [this message]
2022-09-21 21:24   ` [PATCH v10 20/39] KVM: nVMX: hyper-v: Enable L2 TLB flush Sean Christopherson
2022-09-22 16:05   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 21/39] KVM: nSVM: " Vitaly Kuznetsov
2022-09-21 21:31   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 22/39] KVM: x86: Expose Hyper-V L2 TLB flush feature Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 23/39] KVM: selftests: Better XMM read/write helpers Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 24/39] KVM: selftests: Move HYPERV_LINUX_OS_ID definition to a common header Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 25/39] KVM: selftests: Move the function doing Hyper-V hypercall " Vitaly Kuznetsov
2022-09-21 21:51   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 26/39] KVM: selftests: Hyper-V PV IPI selftest Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 27/39] KVM: selftests: Fill in vm->vpages_mapped bitmap in virt_map() too Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 28/39] KVM: selftests: Export vm_vaddr_unused_gap() to make it possible to request unmapped ranges Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 29/39] KVM: selftests: Export _vm_get_page_table_entry() Vitaly Kuznetsov
2022-09-21 22:13   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 30/39] KVM: selftests: Hyper-V PV TLB flush selftest Vitaly Kuznetsov
2022-09-21 22:52   ` Sean Christopherson
2022-10-03 13:01     ` Vitaly Kuznetsov
2022-10-03 15:47       ` Sean Christopherson
2022-10-03 16:00         ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 31/39] KVM: selftests: Sync 'struct hv_enlightened_vmcs' definition with hyperv-tlfs.h Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 32/39] KVM: selftests: Sync 'struct hv_vp_assist_page' " Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 33/39] KVM: selftests: Move Hyper-V VP assist page enablement out of evmcs.h Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 34/39] KVM: selftests: Split off load_evmcs() from load_vmcs() Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 35/39] KVM: selftests: Create a vendor independent helper to allocate Hyper-V specific test pages Vitaly Kuznetsov
2022-09-21 22:59   ` Sean Christopherson
2022-09-21 15:24 ` [PATCH v10 36/39] KVM: selftests: Allocate Hyper-V partition assist page Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 37/39] KVM: selftests: evmcs_test: Introduce L2 TLB flush test Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 38/39] KVM: selftests: hyperv_svm_test: " Vitaly Kuznetsov
2022-09-21 15:24 ` [PATCH v10 39/39] KVM: selftests: Rename 'evmcs_test' to 'hyperv_evmcs' Vitaly Kuznetsov

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