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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: Joerg Roedel <joro@8bytes.org>
Signed-off-by: Alexander Graf <agraf@suse.de>
Signed-off-by: Avi Kivity <avi@redhat.com>
hifive-unleashed-5.1
Alexander Graf 2008-11-25 20:17:03 +01:00 committed by Avi Kivity
parent 9962d032bb
commit c0725420cf
1 changed files with 85 additions and 0 deletions
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85
arch/x86/kvm/svm.c
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@ -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)
{