David S. Ahern wrote: > Avi Kivity wrote: > >> Ah! The flood detector is not seeing the access through the >> kmap_atomic() pte, because that access has gone through the emulator. >> last_updated_pte_accessed(vcpu) will never return true. >> >> Can you verify that last_updated_pte_accessed(vcpu) indeed always >> returns false? >> >> > > It returns both true and false. I added a tracer to kvm_mmu_pte_write() to > dump > the rc of last_updated_pte_accessed(vcpu). ie., > pte_access = last_updated_pte_accessed(vcpu); > KVMTRACE_1D(PTE_ACCESS, vcpu, (u32) pte_access, handler); > > A sample: > > (+ 4488) VMEXIT [ exitcode = 0x00000000, rip = 0x00000000 c016104a ] > (+ 0) PAGE_FAULT [ errorcode = 0x0000000b, virt = 0x00000000 > fffb63b0 ] > (+ 2480) PAGE_FAULT1 [ write_count = 0 ] > (+ 424) PAGE_FAULT2 [ level = 2 metaphysical = 0 access 0x00000007 ] > (+ 51672) PAGE_FAULT3 > (+ 472) PAGE_FAULT4 > (+ 704) PAGE_FAULT5 [ shadow_ent = 0x80000001 2dfb5043 ] > (+ 1496) VMENTRY > (+ 4568) VMEXIT [ exitcode = 0x00000000, rip = 0x00000000 c01610e7 ] > (+ 0) PAGE_FAULT [ errorcode = 0x00000003, virt = 0x00000000 > c0009db4 ] > (+ 2352) PAGE_FAULT1 [ write_count = 0 ] > (+ 728) PAGE_FAULT5 [ shadow_ent = 0x00000001 91409041 ] > (+ 0) PTE_WRITE [ gpa = 0x00000000 00009db4 gpte = 0x00000000 > 41fb5363 ] > (+ 0) PTE_ACCESS [ pte_access = 1 ] > (+ 6864) VMENTRY > (+ 3896) VMEXIT [ exitcode = 0x00000000, rip = 0x00000000 c01610ee ] > (+ 0) PAGE_FAULT [ errorcode = 0x00000003, virt = 0x00000000 > c0009db0 ] > (+ 2376) PAGE_FAULT1 [ write_count = 1 ] > (+ 720) PAGE_FAULT5 [ shadow_ent = 0x00000001 91409041 ] > (+ 0) PTE_WRITE [ gpa = 0x00000000 00009db0 gpte = 0x00000000 > 00000000 ] > (+ 0) PTE_ACCESS [ pte_access = 0 ] > (+ 12344) VMENTRY > (+ 4688) VMEXIT [ exitcode = 0x00000000, rip = 0x00000000 c016127c ] > (+ 0) PAGE_FAULT [ errorcode = 0x00000003, virt = 0x00000000 > c0009db4 ] > (+ 2416) PAGE_FAULT1 [ write_count = 2 ] > (+ 792) PAGE_FAULT5 [ shadow_ent = 0x00000001 91409043 ] > (+ 1128) VMENTRY > (+ 4512) VMEXIT [ exitcode = 0x00000000, rip = 0x00000000 c016104a ] > (+ 0) PAGE_FAULT [ errorcode = 0x0000000b, virt = 0x00000000 > fffb63b0 ] > (+ 2448) PAGE_FAULT1 [ write_count = 0 ] > (+ 448) PAGE_FAULT2 [ level = 2 metaphysical = 0 access 0x00000007 ] > (+ 51520) PAGE_FAULT3 > (+ 432) PAGE_FAULT4 > (+ 696) PAGE_FAULT5 [ shadow_ent = 0x80000001 2df5a043 ] > (+ 1480) VMENTRY > >
Strange... there should be at least two pte_access = 0 traces in there before flooding can occur, according to my reading of the code. The counter needs to go up to 3 somehow. -- Do not meddle in the internals of kernels, for they are subtle and quick to panic. ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ kvm-devel mailing list kvm-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/kvm-devel
