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Commit c0725420 authored by Alexander Graf's avatar Alexander Graf Committed by Avi Kivity
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KVM: SVM: Add helper functions for nested SVM 



These are helpers for the nested SVM implementation.

- nsvm_printk implements a debug printk variant
- nested_svm_do calls a handler that can accesses gpa-based memory

v3 makes use of the new permission checker
v6 changes:
- streamline nsvm_debug()
- remove printk(KERN_ERR)
- SVME check before CPL check
- give GP error code
- use new EFER constant

Acked-by: default avatarJoerg Roedel <joro@8bytes.org>
Signed-off-by: default avatarAlexander Graf <agraf@suse.de>
Signed-off-by: default avatarAvi Kivity <avi@redhat.com>
parent 9962d032

arch/x86/kvm/svm.c

+85 −0
Original line number Diff line number Diff line
@@ -50,6 +50,15 @@ MODULE_LICENSE("GPL"); 


#define DEBUGCTL_RESERVED_BITS (~(0x3fULL))



/* Turn on to get debugging output*/

/* #define NESTED_DEBUG */



#ifdef NESTED_DEBUG

#define nsvm_printk(fmt, args...) printk(KERN_INFO fmt, ## args)

#else

#define nsvm_printk(fmt, args...) do {} while(0)

#endif



/* enable NPT for AMD64 and X86 with PAE */

#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)

static bool npt_enabled = true;
@@ -1149,6 +1158,82 @@ static int vmmcall_interception(struct vcpu_svm *svm, struct kvm_run *kvm_run) 
	return 1;

}



static int nested_svm_check_permissions(struct vcpu_svm *svm)

{

	if (!(svm->vcpu.arch.shadow_efer & EFER_SVME)

	    || !is_paging(&svm->vcpu)) {

		kvm_queue_exception(&svm->vcpu, UD_VECTOR);

		return 1;

	}



	if (svm->vmcb->save.cpl) {

		kvm_inject_gp(&svm->vcpu, 0);

		return 1;

	}



       return 0;

}



static struct page *nested_svm_get_page(struct vcpu_svm *svm, u64 gpa)

{

	struct page *page;



	down_read(&current->mm->mmap_sem);

	page = gfn_to_page(svm->vcpu.kvm, gpa >> PAGE_SHIFT);

	up_read(&current->mm->mmap_sem);



	if (is_error_page(page)) {

		printk(KERN_INFO "%s: could not find page at 0x%llx\n",

		       __func__, gpa);

		kvm_release_page_clean(page);

		kvm_inject_gp(&svm->vcpu, 0);

		return NULL;

	}

	return page;

}



static int nested_svm_do(struct vcpu_svm *svm,

			 u64 arg1_gpa, u64 arg2_gpa, void *opaque,

			 int (*handler)(struct vcpu_svm *svm,

					void *arg1,

					void *arg2,

					void *opaque))

{

	struct page *arg1_page;

	struct page *arg2_page = NULL;

	void *arg1;

	void *arg2 = NULL;

	int retval;



	arg1_page = nested_svm_get_page(svm, arg1_gpa);

	if(arg1_page == NULL)

		return 1;



	if (arg2_gpa) {

		arg2_page = nested_svm_get_page(svm, arg2_gpa);

		if(arg2_page == NULL) {

			kvm_release_page_clean(arg1_page);

			return 1;

		}

	}



	arg1 = kmap_atomic(arg1_page, KM_USER0);

	if (arg2_gpa)

		arg2 = kmap_atomic(arg2_page, KM_USER1);



	retval = handler(svm, arg1, arg2, opaque);



	kunmap_atomic(arg1, KM_USER0);

	if (arg2_gpa)

		kunmap_atomic(arg2, KM_USER1);



	kvm_release_page_dirty(arg1_page);

	if (arg2_gpa)

		kvm_release_page_dirty(arg2_page);



	return retval;

}



static int invalid_op_interception(struct vcpu_svm *svm,

				   struct kvm_run *kvm_run)

{