On 30.10.2008, at 18:56, Anthony Liguori wrote:
Alexander Graf wrote:
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
Signed-off-by: Alexander Graf <[EMAIL PROTECTED]>
---
arch/x86/kvm/svm.c | 88 ++++++++++++++++++++++++++++++++++++++++++
++++++++++
1 files changed, 88 insertions(+), 0 deletions(-)
diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 4ee5376..a00421b 100644
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -48,6 +48,16 @@ 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
+static inline void nsvm_printk(char *fmt, ...) {
+}
+#endif
I understand why you have this form, but stylistically the '{'
should come on the next line. Personally, I'd stick with the
standard do {} while(0) just to avoid confusion although in the
context of the kernel, I think pr_debug() would be better although a
little more annoying to use.
A define to do {} while(0) sounds good. I'll do that.
/* enable NPT for AMD64 and X86 with PAE */
#if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
static bool npt_enabled = true;
@@ -1145,6 +1155,84 @@ 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->vmcb->save.cpl) {
+ printk(KERN_ERR "%s: invalid cpl 0x%x at ip 0x%lx\n",
+ __func__, svm->vmcb->save.cpl, kvm_rip_read(&svm->vcpu));
+ kvm_queue_exception(&svm->vcpu, GP_VECTOR);
GPFs need an error code. Do you really think a GP should be
delivered before checking SVME though? I think you ought to switch
the order of these checks.
Nice catch. The spec also says SVME is checked before CPL.
What error code exactly would we need here?
+ return 1;
+ }
+
+ if (!(svm->vcpu.arch.shadow_efer & MSR_EFER_SVME_MASK)
+ || !is_paging(&svm->vcpu)) {
+ kvm_queue_exception(&svm->vcpu, UD_VECTOR);
+ return 1;
+ }
+
+ return 0;
+}
+
+static struct page *nested_svm_get_page(struct vcpu_svm *svm, u64
gpa)
+{
+ struct page *page;
+
+ down_read(¤t->mm->mmap_sem);
+ page = gfn_to_page(svm->vcpu.kvm, gpa >> PAGE_SHIFT);
+ up_read(¤t->mm->mmap_sem);
+
+ if (is_error_page(page)) {
+ printk(KERN_ERR "%s: could not find page at 0x%llx\n",
+ __func__, gpa);
+ kvm_release_page_clean(page);
+ kvm_queue_exception(&svm->vcpu, GP_VECTOR);
+ 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;
+}
+
I appreciate small patches but introducing statics that aren't used
is going to generate warnings when bisecting. I think that suggests
your splitting things at the wrong level.
I figured warnings are nicer than having a blown-up patch. These
functions are basically used within all patches from that one on, so
it felt logical to split them up this way. How would you have split
them up?
Alex
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