From fcc35e7ccaed771790940524f3b0eef7aebfc9b1 Mon Sep 17 00:00:00 2001 From: "Dr. David Alan Gilbert" Date: Fri, 8 Jul 2016 16:01:38 +0100 Subject: target-i386: Fill high bits of mtrr mask Fill the bits between 51..number-of-physical-address-bits in the MTRR_PHYSMASKn variable range mtrr masks so that they're consistent in the migration stream irrespective of the physical address space of the source VM in a migration. Signed-off-by: Dr. David Alan Gilbert Suggested-by: Paolo Bonzini Reviewed-by: Eduardo Habkost Signed-off-by: Eduardo Habkost --- target-i386/kvm.c | 28 +++++++++++++++++++++++++++- 1 file changed, 27 insertions(+), 1 deletion(-) (limited to 'target-i386/kvm.c') diff --git a/target-i386/kvm.c b/target-i386/kvm.c index 2f1cc62795..df28dd254a 100644 --- a/target-i386/kvm.c +++ b/target-i386/kvm.c @@ -1977,6 +1977,7 @@ static int kvm_get_msrs(X86CPU *cpu) CPUX86State *env = &cpu->env; struct kvm_msr_entry *msrs = cpu->kvm_msr_buf->entries; int ret, i; + uint64_t mtrr_top_bits; kvm_msr_buf_reset(cpu); @@ -2129,6 +2130,30 @@ static int kvm_get_msrs(X86CPU *cpu) } assert(ret == cpu->kvm_msr_buf->nmsrs); + /* + * MTRR masks: Each mask consists of 5 parts + * a 10..0: must be zero + * b 11 : valid bit + * c n-1.12: actual mask bits + * d 51..n: reserved must be zero + * e 63.52: reserved must be zero + * + * 'n' is the number of physical bits supported by the CPU and is + * apparently always <= 52. We know our 'n' but don't know what + * the destinations 'n' is; it might be smaller, in which case + * it masks (c) on loading. It might be larger, in which case + * we fill 'd' so that d..c is consistent irrespetive of the 'n' + * we're migrating to. + */ + + if (cpu->fill_mtrr_mask) { + QEMU_BUILD_BUG_ON(TARGET_PHYS_ADDR_SPACE_BITS > 52); + assert(cpu->phys_bits <= TARGET_PHYS_ADDR_SPACE_BITS); + mtrr_top_bits = MAKE_64BIT_MASK(cpu->phys_bits, 52 - cpu->phys_bits); + } else { + mtrr_top_bits = 0; + } + for (i = 0; i < ret; i++) { uint32_t index = msrs[i].index; switch (index) { @@ -2327,7 +2352,8 @@ static int kvm_get_msrs(X86CPU *cpu) break; case MSR_MTRRphysBase(0) ... MSR_MTRRphysMask(MSR_MTRRcap_VCNT - 1): if (index & 1) { - env->mtrr_var[MSR_MTRRphysIndex(index)].mask = msrs[i].data; + env->mtrr_var[MSR_MTRRphysIndex(index)].mask = msrs[i].data | + mtrr_top_bits; } else { env->mtrr_var[MSR_MTRRphysIndex(index)].base = msrs[i].data; } -- cgit v1.2.3