On 02/09/2010 04:14 PM, Gleb Natapov wrote:
Make emulator check that vcpu is allowed to execute IN, INS, OUT,
OUTS, CLI, STI.
+bool kvm_check_iopl(struct kvm_vcpu *vcpu)
+{
+ int iopl;
+ if (!is_protmode(vcpu))
+ return false;
+ if (kvm_get_rflags(vcpu)& X86_EFLAGS_VM)
+ return true;
+ iopl = (kvm_get_rflags(vcpu)& X86_EFLAGS_IOPL)>> IOPL_SHIFT;
+ return kvm_x86_ops->get_cpl(vcpu)> iopl;
+}
Confusingly named - check doesn't imply what the return value means
(and 'true' is surprising for a failure). Suggest kvm_bad_iopl() or
similar.
+
+bool kvm_check_io_port_access_allowed(struct kvm_vcpu *vcpu, u16 port, u16 len)
+{
Similarly, can drop check_ from the name.
+ struct kvm_segment tr_seg;
+ int r;
+ u16 io_bitmap_ptr;
+ u8 perm, bit_idx = port& 0x7;
+ unsigned mask = (1<< len) - 1;
+
+ kvm_get_segment(vcpu,&tr_seg, VCPU_SREG_TR);
+ if (tr_seg.unusable)
+ return false;
+ if (tr_seg.limit< 103)
+ return false;
+ r = kvm_read_guest_virt_system(tr_seg.base + 102,&io_bitmap_ptr, 2,
+ vcpu, NULL);
+ if (r != X86EMUL_CONTINUE)
+ return false;
+ if (io_bitmap_ptr + port/8>= tr_seg.limit)
+ return false;
Should this be '>'? limits are generally inclusive of the byte read
(i.e. they aren't the size of the segment, but the offset of the last byte).
+ r = kvm_read_guest_virt_system(tr_seg.base + io_bitmap_ptr + port/8,
+ &perm, 1, vcpu, NULL);
+ if (r != X86EMUL_CONTINUE)
+ return false;
+ if ((perm>> bit_idx)& mask)
+ return false;
+ return true;
+}
+
--
error compiling committee.c: too many arguments to function
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