On 12/9/2022 12:45 PM, Robert Hoo wrote
+#ifdef CONFIG_X86_64
+/* untag addr for guest, according to vCPU CR3 and CR4 settings */
+static inline u64 kvm_untagged_addr(u64 addr, struct kvm_vcpu *vcpu)
+{
+ if (addr >> 63 == 0) {
+ /* User pointers */
+ if (kvm_read_cr3(vcpu) & X86_CR3_LAM_U57)
+ addr = get_canonical(addr, 57);
According to the spec, LAM_U57/LAM_SUP also performs a modified
canonicality check.
Why the check only be done for LAM_U48, but not for LAM_U57 and LAM_SUP
cases?
+ else if (kvm_read_cr3(vcpu) & X86_CR3_LAM_U48) {
+ /*
+ * If guest enabled 5-level paging and LAM_U48,
+ * bit 47 should be 0, bit 48:56 contains meta data
+ * although bit 47:56 are valid 5-level address
+ * bits.
+ * If LAM_U48 and 4-level paging, bit47 is 0.
+ */
+ WARN_ON(addr & _BITUL(47));
+ addr = get_canonical(addr, 48);
+ }
+ } else if (kvm_read_cr4(vcpu) & X86_CR4_LAM_SUP) { /* Supervisor pointers */
+ if (kvm_read_cr4(vcpu) & X86_CR4_LA57)
+ addr = get_canonical(addr, 57);
+ else
+ addr = get_canonical(addr, 48);
+ }
+
+ return addr;
+}
+#else
+#define kvm_untagged_addr(addr, vcpu) (addr)
+#endif
+
static inline void vcpu_cache_mmio_info(struct kvm_vcpu *vcpu,
gva_t gva, gfn_t gfn, unsigned access)
{
