Commit a9dd6f09 authored by Sean Christopherson's avatar Sean Christopherson Committed by Paolo Bonzini
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KVM: x86: Allocate vcpu struct in common x86 code 



Move allocation of VMX and SVM vcpus to common x86.  Although the struct
being allocated is technically a VMX/SVM struct, it can be interpreted
directly as a 'struct kvm_vcpu' because of the pre-existing requirement
that 'struct kvm_vcpu' be located at offset zero of the arch/vendor vcpu
struct.

Remove the message from the build-time assertions regarding placement of
the struct, as compatibility with the arch usercopy region is no longer
the sole dependent on 'struct kvm_vcpu' being at offset zero.

Signed-off-by: default avatarSean Christopherson <sean.j.christopherson@intel.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 7f27179a

arch/x86/include/asm/kvm_host.h

+1 −1
Original line number Diff line number Diff line
@@ -1050,7 +1050,7 @@ struct kvm_x86_ops { 
	void (*vm_destroy)(struct kvm *kvm);



	/* Create, but do not attach this VCPU */

	struct kvm_vcpu *(*vcpu_create)(struct kvm *kvm, unsigned id);

	int (*vcpu_create)(struct kvm *kvm, struct kvm_vcpu *vcpu, unsigned id);

	void (*vcpu_free)(struct kvm_vcpu *vcpu);

	void (*vcpu_reset)(struct kvm_vcpu *vcpu, bool init_event);

arch/x86/kvm/svm.c

+9 −19
Original line number Diff line number Diff line
@@ -2187,9 +2187,9 @@ static int avic_init_vcpu(struct vcpu_svm *svm) 
	return ret;

}



static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id)

static int svm_create_vcpu(struct kvm *kvm, struct kvm_vcpu *vcpu,

			   unsigned int id)

{

	struct kvm_vcpu *vcpu;

	struct vcpu_svm *svm;

	struct page *page;

	struct page *msrpm_pages;
@@ -2197,22 +2197,15 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) 
	struct page *nested_msrpm_pages;

	int err;



	BUILD_BUG_ON_MSG(offsetof(struct vcpu_svm, vcpu) != 0,

		"struct kvm_vcpu must be at offset 0 for arch usercopy region");



	svm = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);

	if (!svm) {

		err = -ENOMEM;

		goto out;

	}

	vcpu = &svm->vcpu;

	BUILD_BUG_ON(offsetof(struct vcpu_svm, vcpu) != 0);

	svm = to_svm(vcpu);



	vcpu->arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache,

						GFP_KERNEL_ACCOUNT);

	if (!vcpu->arch.user_fpu) {

		printk(KERN_ERR "kvm: failed to allocate kvm userspace's fpu\n");

		err = -ENOMEM;

		goto free_partial_svm;

		goto out;

	}



	vcpu->arch.guest_fpu = kmem_cache_zalloc(x86_fpu_cache,
@@ -2225,7 +2218,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) 


	err = kvm_vcpu_init(vcpu, kvm, id);

	if (err)

		goto free_svm;

		goto free_guest_fpu;



	err = -ENOMEM;

	page = alloc_page(GFP_KERNEL_ACCOUNT);
@@ -2269,7 +2262,7 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) 


	svm_init_osvw(vcpu);



	return vcpu;

	return 0;



free_page4:

	__free_page(hsave_page);
@@ -2281,14 +2274,12 @@ static struct kvm_vcpu *svm_create_vcpu(struct kvm *kvm, unsigned int id) 
	__free_page(page);

uninit:

	kvm_vcpu_uninit(vcpu);

free_svm:

free_guest_fpu:

	kmem_cache_free(x86_fpu_cache, vcpu->arch.guest_fpu);

free_user_fpu:

	kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu);

free_partial_svm:

	kmem_cache_free(kvm_vcpu_cache, svm);

out:

	return ERR_PTR(err);

	return err;

}



static void svm_clear_current_vmcb(struct vmcb *vmcb)
@@ -2317,7 +2308,6 @@ static void svm_free_vcpu(struct kvm_vcpu *vcpu) 
	kvm_vcpu_uninit(vcpu);

	kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu);

	kmem_cache_free(x86_fpu_cache, vcpu->arch.guest_fpu);

	kmem_cache_free(kvm_vcpu_cache, svm);

}



static void svm_vcpu_load(struct kvm_vcpu *vcpu, int cpu)

arch/x86/kvm/vmx/vmx.c

+8 −16
Original line number Diff line number Diff line
@@ -6684,31 +6684,24 @@ static void vmx_free_vcpu(struct kvm_vcpu *vcpu) 
	kvm_vcpu_uninit(vcpu);

	kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu);

	kmem_cache_free(x86_fpu_cache, vcpu->arch.guest_fpu);

	kmem_cache_free(kvm_vcpu_cache, vmx);

}



static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id)

static int vmx_create_vcpu(struct kvm *kvm, struct kvm_vcpu *vcpu,

			   unsigned int id)

{

	struct kvm_vcpu *vcpu;

	struct vcpu_vmx *vmx;

	unsigned long *msr_bitmap;

	int i, cpu, err;



	BUILD_BUG_ON_MSG(offsetof(struct vcpu_vmx, vcpu) != 0,

		"struct kvm_vcpu must be at offset 0 for arch usercopy region");



	vmx = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);

	if (!vmx)

		return ERR_PTR(-ENOMEM);



	vcpu = &vmx->vcpu;

	BUILD_BUG_ON(offsetof(struct vcpu_vmx, vcpu) != 0);

	vmx = to_vmx(vcpu);



	vcpu->arch.user_fpu = kmem_cache_zalloc(x86_fpu_cache,

						GFP_KERNEL_ACCOUNT);

	if (!vcpu->arch.user_fpu) {

		printk(KERN_ERR "kvm: failed to allocate kvm userspace's fpu\n");

		err = -ENOMEM;

		goto free_partial_vcpu;

		goto out;

	}



	vcpu->arch.guest_fpu = kmem_cache_zalloc(x86_fpu_cache,
@@ -6829,7 +6822,7 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) 


	vmx->ept_pointer = INVALID_PAGE;



	return vcpu;

	return 0;



free_vmcs:

	free_loaded_vmcs(vmx->loaded_vmcs);
@@ -6842,9 +6835,8 @@ static struct kvm_vcpu *vmx_create_vcpu(struct kvm *kvm, unsigned int id) 
	kmem_cache_free(x86_fpu_cache, vcpu->arch.guest_fpu);

free_user_fpu:

	kmem_cache_free(x86_fpu_cache, vcpu->arch.user_fpu);

free_partial_vcpu:

	kmem_cache_free(kvm_vcpu_cache, vmx);

	return ERR_PTR(err);

out:

	return err;

}



#define L1TF_MSG_SMT "L1TF CPU bug present and SMT on, data leak possible. See CVE-2018-3646 and https://www.kernel.org/doc/html/latest/admin-guide/hw-vuln/l1tf.html for details.\n"

arch/x86/kvm/x86.c

+12 −4
Original line number Diff line number Diff line
@@ -9172,26 +9172,34 @@ static void fx_init(struct kvm_vcpu *vcpu) 


void kvm_arch_vcpu_free(struct kvm_vcpu *vcpu)

{

	void *wbinvd_dirty_mask = vcpu->arch.wbinvd_dirty_mask;



	kvmclock_reset(vcpu);



	kvm_x86_ops->vcpu_free(vcpu);

	free_cpumask_var(wbinvd_dirty_mask);



	free_cpumask_var(vcpu->arch.wbinvd_dirty_mask);

	kmem_cache_free(kvm_vcpu_cache, vcpu);

}



struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm,

						unsigned int id)

{

	struct kvm_vcpu *vcpu;

	int r;



	if (kvm_check_tsc_unstable() && atomic_read(&kvm->online_vcpus) != 0)

		printk_once(KERN_WARNING

		"kvm: SMP vm created on host with unstable TSC; "

		"guest TSC will not be reliable\n");



	vcpu = kvm_x86_ops->vcpu_create(kvm, id);

	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL_ACCOUNT);

	if (!vcpu)

		return ERR_PTR(-ENOMEM);



	r = kvm_x86_ops->vcpu_create(kvm, vcpu, id);

	if (r) {

		kmem_cache_free(kvm_vcpu_cache, vcpu);

		return ERR_PTR(r);

	}

	return vcpu;

}