From e7d230ede0deb239271a25d227a792ae615daee2 Mon Sep 17 00:00:00 2001 From: Andreas Sandberg Date: Mon, 3 Mar 2014 14:34:33 +0100 Subject: kvm: x86: Always assume segments to be usable When transferring segment registers into kvm, we need to find the value of the unusable bit. We used to assume that this could be inferred from the selector since segments are generally unusable if their selector is 0. This assumption breaks in some weird corner cases. Instead, we just assume that segments are always usable. This is what qemu does so it should work. --- src/cpu/kvm/x86_cpu.cc | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) (limited to 'src/cpu/kvm') diff --git a/src/cpu/kvm/x86_cpu.cc b/src/cpu/kvm/x86_cpu.cc index 8f7ca19e4..b79207fab 100644 --- a/src/cpu/kvm/x86_cpu.cc +++ b/src/cpu/kvm/x86_cpu.cc @@ -721,11 +721,11 @@ setKvmSegmentReg(ThreadContext *tc, struct kvm_segment &kvm_seg, kvm_seg.g = attr.granularity; kvm_seg.avl = attr.avl; - // A segment is unusable when the selector is zero. There is a - // attr.unusable flag in gem5, but it seems unused. - // - // TODO: Are there corner cases where this doesn't work? - kvm_seg.unusable = (kvm_seg.selector == 0); + // A segment is normally unusable when the selector is zero. There + // is a attr.unusable flag in gem5, but it seems unused. qemu + // seems to set this to 0 all the time, so we just do the same and + // hope for the best. + kvm_seg.unusable = 0; } static inline void -- cgit v1.2.3