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From: Paolo Bonzini <pbonzini@redhat.com>
To: linux-kernel@vger.kernel.org, kvm@vger.kernel.org
Cc: Sean Christopherson <sean.j.christopherson@intel.com>,
	vkuznets@redhat.com
Subject: [PATCH 19/43] KVM: VMX: simplify vmx_prepare_switch_to_{guest,host}
Date: Thu, 13 Jun 2019 19:03:05 +0200
Message-ID: <1560445409-17363-20-git-send-email-pbonzini@redhat.com> (raw)
In-Reply-To: <1560445409-17363-1-git-send-email-pbonzini@redhat.com>

vmx->loaded_cpu_state can only be NULL or equal to vmx->loaded_vmcs,
so change it to a bool.  Because the direction of the bool is
now the opposite of vmx->guest_msrs_dirty, change the direction of
vmx->guest_msrs_dirty so that they match.

Finally, do not imply that MSRs have to be reloaded when
vmx->guest_state_loaded is false; instead, set vmx->guest_msrs_ready
to false explicitly in vmx_prepare_switch_to_host.

Cc: Sean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 arch/x86/kvm/vmx/vmx.c | 26 +++++++++++++-------------
 arch/x86/kvm/vmx/vmx.h | 18 ++++++++++++------
 2 files changed, 25 insertions(+), 19 deletions(-)

diff --git a/arch/x86/kvm/vmx/vmx.c b/arch/x86/kvm/vmx/vmx.c
index 091610684d28..40a6235bc4d8 100644
--- a/arch/x86/kvm/vmx/vmx.c
+++ b/arch/x86/kvm/vmx/vmx.c
@@ -1057,20 +1057,18 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
 	 * when guest state is loaded. This happens when guest transitions
 	 * to/from long-mode by setting MSR_EFER.LMA.
 	 */
-	if (!vmx->loaded_cpu_state || vmx->guest_msrs_dirty) {
-		vmx->guest_msrs_dirty = false;
+	if (!vmx->guest_msrs_ready) {
+		vmx->guest_msrs_ready = true;
 		for (i = 0; i < vmx->save_nmsrs; ++i)
 			kvm_set_shared_msr(vmx->guest_msrs[i].index,
 					   vmx->guest_msrs[i].data,
 					   vmx->guest_msrs[i].mask);
 
 	}
-
-	if (vmx->loaded_cpu_state)
+	if (vmx->guest_state_loaded)
 		return;
 
-	vmx->loaded_cpu_state = vmx->loaded_vmcs;
-	host_state = &vmx->loaded_cpu_state->host_state;
+	host_state = &vmx->loaded_vmcs->host_state;
 
 	/*
 	 * Set host fs and gs selectors.  Unfortunately, 22.2.3 does not
@@ -1126,20 +1124,20 @@ void vmx_prepare_switch_to_guest(struct kvm_vcpu *vcpu)
 		vmcs_writel(HOST_GS_BASE, gs_base);
 		host_state->gs_base = gs_base;
 	}
+
+	vmx->guest_state_loaded = true;
 }
 
 static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx)
 {
 	struct vmcs_host_state *host_state;
 
-	if (!vmx->loaded_cpu_state)
+	if (!vmx->guest_state_loaded)
 		return;
 
-	WARN_ON_ONCE(vmx->loaded_cpu_state != vmx->loaded_vmcs);
-	host_state = &vmx->loaded_cpu_state->host_state;
+	host_state = &vmx->loaded_vmcs->host_state;
 
 	++vmx->vcpu.stat.host_state_reload;
-	vmx->loaded_cpu_state = NULL;
 
 #ifdef CONFIG_X86_64
 	rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
@@ -1165,13 +1163,15 @@ static void vmx_prepare_switch_to_host(struct vcpu_vmx *vmx)
 	wrmsrl(MSR_KERNEL_GS_BASE, vmx->msr_host_kernel_gs_base);
 #endif
 	load_fixmap_gdt(raw_smp_processor_id());
+	vmx->guest_state_loaded = false;
+	vmx->guest_msrs_ready = false;
 }
 
 #ifdef CONFIG_X86_64
 static u64 vmx_read_guest_kernel_gs_base(struct vcpu_vmx *vmx)
 {
 	preempt_disable();
-	if (vmx->loaded_cpu_state)
+	if (vmx->guest_state_loaded)
 		rdmsrl(MSR_KERNEL_GS_BASE, vmx->msr_guest_kernel_gs_base);
 	preempt_enable();
 	return vmx->msr_guest_kernel_gs_base;
@@ -1180,7 +1180,7 @@ static u64 vmx_read_guest_kernel_gs_base(struct vcpu_vmx *vmx)
 static void vmx_write_guest_kernel_gs_base(struct vcpu_vmx *vmx, u64 data)
 {
 	preempt_disable();
-	if (vmx->loaded_cpu_state)
+	if (vmx->guest_state_loaded)
 		wrmsrl(MSR_KERNEL_GS_BASE, data);
 	preempt_enable();
 	vmx->msr_guest_kernel_gs_base = data;
@@ -1583,7 +1583,7 @@ static void setup_msrs(struct vcpu_vmx *vmx)
 		move_msr_up(vmx, index, save_nmsrs++);
 
 	vmx->save_nmsrs = save_nmsrs;
-	vmx->guest_msrs_dirty = true;
+	vmx->guest_msrs_ready = false;
 
 	if (cpu_has_vmx_msr_bitmap())
 		vmx_update_msr_bitmap(&vmx->vcpu);
diff --git a/arch/x86/kvm/vmx/vmx.h b/arch/x86/kvm/vmx/vmx.h
index ed65999b07a8..f35442093397 100644
--- a/arch/x86/kvm/vmx/vmx.h
+++ b/arch/x86/kvm/vmx/vmx.h
@@ -187,13 +187,23 @@ struct vcpu_vmx {
 	struct kvm_vcpu       vcpu;
 	u8                    fail;
 	u8		      msr_bitmap_mode;
+
+	/*
+	 * If true, host state has been stored in vmx->loaded_vmcs for
+	 * the CPU registers that only need to be switched when transitioning
+	 * to/from the kernel, and the registers have been loaded with guest
+	 * values.  If false, host state is loaded in the CPU registers
+	 * and vmx->loaded_vmcs->host_state is invalid.
+	 */
+	bool		      guest_state_loaded;
+
 	u32                   exit_intr_info;
 	u32                   idt_vectoring_info;
 	ulong                 rflags;
 	struct shared_msr_entry *guest_msrs;
 	int                   nmsrs;
 	int                   save_nmsrs;
-	bool                  guest_msrs_dirty;
+	bool                  guest_msrs_ready;
 #ifdef CONFIG_X86_64
 	u64		      msr_host_kernel_gs_base;
 	u64		      msr_guest_kernel_gs_base;
@@ -208,14 +218,10 @@ struct vcpu_vmx {
 	/*
 	 * loaded_vmcs points to the VMCS currently used in this vcpu. For a
 	 * non-nested (L1) guest, it always points to vmcs01. For a nested
-	 * guest (L2), it points to a different VMCS.  loaded_cpu_state points
-	 * to the VMCS whose state is loaded into the CPU registers that only
-	 * need to be switched when transitioning to/from the kernel; a NULL
-	 * value indicates that host state is loaded.
+	 * guest (L2), it points to a different VMCS.
 	 */
 	struct loaded_vmcs    vmcs01;
 	struct loaded_vmcs   *loaded_vmcs;
-	struct loaded_vmcs   *loaded_cpu_state;
 
 	struct msr_autoload {
 		struct vmx_msrs guest;
-- 
1.8.3.1



  parent reply index

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-06-13 17:02 [PATCH 00/43] VMX optimizations Paolo Bonzini
2019-06-13 17:02 ` [PATCH 01/43] KVM: VMX: Fix handling of #MC that occurs during VM-Entry Paolo Bonzini
2019-06-13 17:24   ` Jim Mattson
2019-06-13 17:02 ` [PATCH 02/43] kvm: nVMX: small cleanup in handle_exception Paolo Bonzini
2019-06-13 17:02 ` [PATCH 03/43] KVM: VMX: Read cached VM-Exit reason to detect external interrupt Paolo Bonzini
2019-06-13 17:02 ` [PATCH 04/43] KVM: VMX: Store the host kernel's IDT base in a global variable Paolo Bonzini
2019-06-13 17:02 ` [PATCH 05/43] KVM: x86: Move kvm_{before,after}_interrupt() calls to vendor code Paolo Bonzini
2019-06-13 17:02 ` [PATCH 06/43] KVM: VMX: Handle NMIs, #MCs and async #PFs in common irqs-disabled fn Paolo Bonzini
2019-06-13 17:02 ` [PATCH 07/43] KVM: nVMX: Intercept VMWRITEs to read-only shadow VMCS fields Paolo Bonzini
2019-06-13 17:02 ` [PATCH 08/43] KVM: nVMX: Intercept VMWRITEs to GUEST_{CS,SS}_AR_BYTES Paolo Bonzini
2019-06-13 17:02 ` [PATCH 09/43] KVM: nVMX: Track vmcs12 offsets for shadowed VMCS fields Paolo Bonzini
2019-06-13 17:02 ` [PATCH 10/43] KVM: nVMX: Lift sync_vmcs12() out of prepare_vmcs12() Paolo Bonzini
2019-06-13 17:02 ` [PATCH 11/43] KVM: nVMX: Use descriptive names for VMCS sync functions and flags Paolo Bonzini
2019-06-13 17:02 ` [PATCH 12/43] KVM: nVMX: Add helpers to identify shadowed VMCS fields Paolo Bonzini
2019-06-14 16:10   ` Sean Christopherson
2019-06-13 17:02 ` [PATCH 13/43] KVM: nVMX: Sync rarely accessed guest fields only when needed Paolo Bonzini
2019-06-13 17:03 ` [PATCH 14/43] KVM: nVMX: Rename prepare_vmcs02_*_full to prepare_vmcs02_*_rare Paolo Bonzini
2019-06-13 17:03 ` [PATCH 15/43] KVM: VMX: Always signal #GP on WRMSR to MSR_IA32_CR_PAT with bad value Paolo Bonzini
2019-06-13 17:03 ` [PATCH 16/43] KVM: nVMX: Always sync GUEST_BNDCFGS when it comes from vmcs01 Paolo Bonzini
     [not found]   ` <20190615221602.93C5721851@mail.kernel.org>
2019-06-15 22:40     ` Liran Alon
2019-06-13 17:03 ` [PATCH 17/43] KVM: nVMX: Write ENCLS-exiting bitmap once per vmcs02 Paolo Bonzini
2019-06-13 17:03 ` [PATCH 18/43] KVM: nVMX: Don't rewrite GUEST_PML_INDEX during nested VM-Entry Paolo Bonzini
2019-06-13 17:03 ` Paolo Bonzini [this message]
2019-06-13 17:03 ` [PATCH 20/43] KVM: nVMX: Don't "put" vCPU or host state when switching VMCS Paolo Bonzini
2019-06-13 17:03 ` [PATCH 21/43] KVM: nVMX: Don't reread VMCS-agnostic " Paolo Bonzini
2019-06-14 16:25   ` Sean Christopherson
2019-06-13 17:03 ` [PATCH 22/43] KVM: nVMX: Don't dump VMCS if virtual APIC page can't be mapped Paolo Bonzini
2019-06-17 19:17   ` Radim Krčmář
2019-06-17 20:07     ` Sean Christopherson
2019-06-18  9:43       ` Paolo Bonzini
2019-06-13 17:03 ` [PATCH 23/43] KVM: nVMX: Don't speculatively write virtual-APIC page address Paolo Bonzini
2019-06-13 17:03 ` [PATCH 24/43] KVM: nVMX: Don't speculatively write APIC-access " Paolo Bonzini
2019-06-13 17:03 ` [PATCH 25/43] KVM: nVMX: Update vmcs12 for MSR_IA32_CR_PAT when it's written Paolo Bonzini
2019-06-13 17:03 ` [PATCH 26/43] KVM: nVMX: Update vmcs12 for SYSENTER MSRs when they're written Paolo Bonzini
2019-06-13 17:03 ` [PATCH 27/43] KVM: nVMX: Update vmcs12 for MSR_IA32_DEBUGCTLMSR when it's written Paolo Bonzini
2019-06-13 17:03 ` [PATCH 28/43] KVM: nVMX: Don't update GUEST_BNDCFGS if it's clean in HV eVMCS Paolo Bonzini
2019-06-13 17:03 ` [PATCH 29/43] KVM: x86: introduce is_pae_paging Paolo Bonzini
2019-06-13 17:03 ` [PATCH 30/43] KVM: nVMX: Copy PDPTRs to/from vmcs12 only when necessary Paolo Bonzini
2019-06-13 17:03 ` [PATCH 31/43] KVM: nVMX: Use adjusted pin controls for vmcs02 Paolo Bonzini
2019-06-13 17:03 ` [PATCH 32/43] KVM: VMX: Add builder macros for shadowing controls Paolo Bonzini
2019-06-13 17:03 ` [PATCH 33/43] KVM: VMX: Shadow VMCS pin controls Paolo Bonzini
2019-06-13 17:03 ` [PATCH 34/43] KVM: VMX: Shadow VMCS primary execution controls Paolo Bonzini
2019-06-13 17:03 ` [PATCH 35/43] KVM: VMX: Shadow VMCS secondary " Paolo Bonzini
2019-06-13 17:03 ` [PATCH 36/43] KVM: nVMX: Shadow VMCS controls on a per-VMCS basis Paolo Bonzini
2019-06-13 17:03 ` [PATCH 37/43] KVM: nVMX: Don't reset VMCS controls shadow on VMCS switch Paolo Bonzini
2019-06-13 17:03 ` [PATCH 38/43] KVM: VMX: Explicitly initialize controls shadow at VMCS allocation Paolo Bonzini
2019-06-13 17:03 ` [PATCH 39/43] KVM: nVMX: Preserve last USE_MSR_BITMAPS when preparing vmcs02 Paolo Bonzini
2019-06-13 17:03 ` [PATCH 40/43] KVM: nVMX: Preset *DT exiting in vmcs02 when emulating UMIP Paolo Bonzini
2019-06-13 17:03 ` [PATCH 41/43] KVM: VMX: Drop hv_timer_armed from 'struct loaded_vmcs' Paolo Bonzini
2019-06-13 17:03 ` [PATCH 42/43] KVM: VMX: Leave preemption timer running when it's disabled Paolo Bonzini
2019-06-14 16:34   ` Sean Christopherson
2019-06-13 17:03 ` [PATCH 43/43] KVM: nVMX: shadow pin based execution controls Paolo Bonzini
2019-06-14 16:34   ` Sean Christopherson

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