diff options
| -rw-r--r-- | src/cpu/kvm/x86_cpu.cc | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/src/cpu/kvm/x86_cpu.cc b/src/cpu/kvm/x86_cpu.cc index 61acc59b7..9e7571b4e 100644 --- a/src/cpu/kvm/x86_cpu.cc +++ b/src/cpu/kvm/x86_cpu.cc @@ -275,6 +275,156 @@ dumpKvm(const struct kvm_vcpu_events &events) inform("\tFlags: 0x%x\n", events.flags); } +static bool +isCanonicalAddress(uint64_t addr) +{ + // x86-64 doesn't currently use the full 64-bit virtual address + // space, instead it uses signed 48 bit addresses that are + // sign-extended to 64 bits. Such addresses are known as + // "canonical". + uint64_t upper_half(addr & 0xffff800000000000ULL); + return upper_half == 0 || upper_half == 0xffff800000000000; +} + +static void +checkSeg(const char *name, const int idx, const struct kvm_segment &seg, + struct kvm_sregs sregs) +{ + // Check the register base + switch (idx) { + case MISCREG_TSL: + case MISCREG_TR: + case MISCREG_FS: + case MISCREG_GS: + if (!isCanonicalAddress(seg.base)) + warn("Illegal %s base: 0x%x\n", name, seg.base); + break; + + case MISCREG_SS: + case MISCREG_DS: + case MISCREG_ES: + if (seg.unusable) + break; + case MISCREG_CS: + if (seg.base & 0xffffffff00000000ULL) + warn("Illegal %s base: 0x%x\n", name, seg.base); + break; + } + + // Check the type + switch (idx) { + case MISCREG_CS: + switch (seg.type) { + case 3: + if (seg.dpl != 0) + warn("CS type is 3 but dpl != 0.\n"); + break; + case 9: + case 11: + if (seg.dpl != sregs.ss.dpl) + warn("CS type is %i but CS DPL != SS DPL\n", seg.type); + break; + case 13: + case 15: + if (seg.dpl > sregs.ss.dpl) + warn("CS type is %i but CS DPL > SS DPL\n", seg.type); + break; + default: + warn("Illegal CS type: %i\n", seg.type); + break; + } + break; + + case MISCREG_SS: + if (seg.unusable) + break; + switch (seg.type) { + case 3: + if (sregs.cs.type == 3 && seg.dpl != 0) + warn("CS type is 3, but SS DPL is != 0.\n"); + /* FALLTHROUGH */ + case 7: + if (!(sregs.cr0 & 1) && seg.dpl != 0) + warn("SS DPL is %i, but CR0 PE is 0\n", seg.dpl); + break; + default: + warn("Illegal SS type: %i\n", seg.type); + break; + } + break; + + case MISCREG_DS: + case MISCREG_ES: + case MISCREG_FS: + case MISCREG_GS: + if (seg.unusable) + break; + if (!(seg.type & 0x1) || + ((seg.type & 0x8) && !(seg.type & 0x2))) + warn("%s has an illegal type field: %i\n", name, seg.type); + break; + + case MISCREG_TR: + // TODO: We should check the CPU mode + if (seg.type != 3 && seg.type != 11) + warn("%s: Illegal segment type (%i)\n", name, seg.type); + break; + + case MISCREG_TSL: + if (seg.unusable) + break; + if (seg.type != 2) + warn("%s: Illegal segment type (%i)\n", name, seg.type); + break; + } + + switch (idx) { + case MISCREG_SS: + case MISCREG_DS: + case MISCREG_ES: + case MISCREG_FS: + case MISCREG_GS: + if (seg.unusable) + break; + case MISCREG_CS: + if (!seg.s) + warn("%s: S flag not set\n", name); + break; + + case MISCREG_TSL: + if (seg.unusable) + break; + case MISCREG_TR: + if (seg.s) + warn("%s: S flag is set\n", name); + break; + } + + switch (idx) { + case MISCREG_SS: + case MISCREG_DS: + case MISCREG_ES: + case MISCREG_FS: + case MISCREG_GS: + case MISCREG_TSL: + if (seg.unusable) + break; + case MISCREG_TR: + case MISCREG_CS: + if (!seg.present) + warn("%s: P flag not set\n", name); + + if (((seg.limit & 0xFFF) == 0 && seg.g) || + ((seg.limit & 0xFFF00000) != 0 && !seg.g)) { + warn("%s limit (0x%x) and g (%i) combination is illegal.\n", + name, seg.limit, seg.g); + } + break; + } + + // TODO: Check CS DB +} + X86KvmCPU::X86KvmCPU(X86KvmCPUParams *params) : BaseKvmCPU(params) { @@ -505,6 +655,18 @@ X86KvmCPU::updateKvmStateSRegs() // Clear the interrupt bitmap memset(&sregs.interrupt_bitmap, 0, sizeof(sregs.interrupt_bitmap)); + RFLAGS rflags_nocc(tc->readMiscReg(MISCREG_RFLAGS)); + if (!rflags_nocc.vm) { + // Do segment verification if the CPU isn't entering virtual + // 8086 mode. We currently assume that unrestricted guest + // mode is available. + +#define APPLY_SEGMENT(kreg, idx) \ + checkSeg(# kreg, idx + MISCREG_SEG_SEL_BASE, sregs.kreg, sregs) + + FOREACH_SEGMENT(); +#undef APPLY_SEGMENT + } setSpecialRegisters(sregs); } void |