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target-i386: Fill high bits of mtrr mask

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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 <dgilbert@redhat.com>
Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Eduardo Habkost <ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
This commit is contained in:
Dr. David Alan Gilbert 2016-07-08 16:01:38 +01:00 committed by Eduardo Habkost
parent 112dad69d7
commit fcc35e7cca
4 changed files with 36 additions and 1 deletions
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5
include/hw/i386/pc.h
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@ -377,6 +377,11 @@ bool e820_get_entry(int, uint32_t, uint64_t *, uint64_t *);
.driver = "vmxnet3",\
.property = "romfile",\
.value = "",\
},\
{\
.driver = TYPE_X86_CPU,\
.property = "fill-mtrr-mask",\
.value = "off",\
},
#define PC_COMPAT_2_5 \

1
target-i386/cpu.c
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@ -3328,6 +3328,7 @@ static Property x86_cpu_properties[] = {
DEFINE_PROP_BOOL("enforce", X86CPU, enforce_cpuid, false),
DEFINE_PROP_BOOL("kvm", X86CPU, expose_kvm, true),
DEFINE_PROP_UINT32("phys-bits", X86CPU, phys_bits, 0),
DEFINE_PROP_BOOL("fill-mtrr-mask", X86CPU, fill_mtrr_mask, true),
DEFINE_PROP_UINT32("level", X86CPU, env.cpuid_level, 0),
DEFINE_PROP_UINT32("xlevel", X86CPU, env.cpuid_xlevel, 0),
DEFINE_PROP_UINT32("xlevel2", X86CPU, env.cpuid_xlevel2, 0),

3
target-i386/cpu.h
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@ -1198,6 +1198,9 @@ struct X86CPU {
/* Compatibility bits for old machine types: */
bool enable_cpuid_0xb;
/* if true fill the top bits of the MTRR_PHYSMASKn variable range */
bool fill_mtrr_mask;
/* Number of physical address bits supported */
uint32_t phys_bits;

28
target-i386/kvm.c
View File

@ -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;
}