diff options
Diffstat (limited to 'target-i386')
| -rw-r--r-- | target-i386/cpu.c | 72 | ||||
| -rw-r--r-- | target-i386/cpu.h | 3 |
2 files changed, 65 insertions, 10 deletions
diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 5fc01c61dc..89ca3268d4 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -2922,6 +2922,31 @@ static void x86_cpu_apic_realize(X86CPU *cpu, Error **errp) } #endif +/* Note: Only safe for use on x86(-64) hosts */ +static uint32_t x86_host_phys_bits(void) +{ + uint32_t eax; + uint32_t host_phys_bits; + + host_cpuid(0x80000000, 0, &eax, NULL, NULL, NULL); + if (eax >= 0x80000008) { + host_cpuid(0x80000008, 0, &eax, NULL, NULL, NULL); + /* Note: According to AMD doc 25481 rev 2.34 they have a field + * at 23:16 that can specify a maximum physical address bits for + * the guest that can override this value; but I've not seen + * anything with that set. + */ + host_phys_bits = eax & 0xff; + } else { + /* It's an odd 64 bit machine that doesn't have the leaf for + * physical address bits; fall back to 36 that's most older + * Intel. + */ + host_phys_bits = 36; + } + + return host_phys_bits; +} #define IS_INTEL_CPU(env) ((env)->cpuid_vendor1 == CPUID_VENDOR_INTEL_1 && \ (env)->cpuid_vendor2 == CPUID_VENDOR_INTEL_2 && \ @@ -2989,29 +3014,55 @@ static void x86_cpu_realizefn(DeviceState *dev, Error **errp) & CPUID_EXT2_AMD_ALIASES); } + /* For 64bit systems think about the number of physical bits to present. + * ideally this should be the same as the host; anything other than matching + * the host can cause incorrect guest behaviour. + * QEMU used to pick the magic value of 40 bits that corresponds to + * consumer AMD devices but nothing else. + */ if (env->features[FEAT_8000_0001_EDX] & CPUID_EXT2_LM) { - /* 0 means it was not explicitly set by the user (or by machine - * compat_props). In this case, the default is the value used by - * TCG (40). - */ - if (cpu->phys_bits == 0) { - cpu->phys_bits = TCG_PHYS_ADDR_BITS; - } if (kvm_enabled()) { - if (cpu->phys_bits > TARGET_PHYS_ADDR_SPACE_BITS || - cpu->phys_bits < 32) { + uint32_t host_phys_bits = x86_host_phys_bits(); + static bool warned; + + if (cpu->host_phys_bits) { + /* The user asked for us to use the host physical bits */ + cpu->phys_bits = host_phys_bits; + } + + /* Print a warning if the user set it to a value that's not the + * host value. + */ + if (cpu->phys_bits != host_phys_bits && cpu->phys_bits != 0 && + !warned) { + error_report("Warning: Host physical bits (%u)" + " does not match phys-bits property (%u)", + host_phys_bits, cpu->phys_bits); + warned = true; + } + + if (cpu->phys_bits && + (cpu->phys_bits > TARGET_PHYS_ADDR_SPACE_BITS || + cpu->phys_bits < 32)) { error_setg(errp, "phys-bits should be between 32 and %u " " (but is %u)", TARGET_PHYS_ADDR_SPACE_BITS, cpu->phys_bits); return; } } else { - if (cpu->phys_bits != TCG_PHYS_ADDR_BITS) { + if (cpu->phys_bits && cpu->phys_bits != TCG_PHYS_ADDR_BITS) { error_setg(errp, "TCG only supports phys-bits=%u", TCG_PHYS_ADDR_BITS); return; } } + /* 0 means it was not explicitly set by the user (or by machine + * compat_props or by the host code above). In this case, the default + * is the value used by TCG (40). + */ + if (cpu->phys_bits == 0) { + cpu->phys_bits = TCG_PHYS_ADDR_BITS; + } } else { /* For 32 bit systems don't use the user set value, but keep * phys_bits consistent with what we tell the guest. @@ -3328,6 +3379,7 @@ 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("host-phys-bits", X86CPU, host_phys_bits, false), 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), diff --git a/target-i386/cpu.h b/target-i386/cpu.h index 10d562d4ea..0ff88e155a 100644 --- a/target-i386/cpu.h +++ b/target-i386/cpu.h @@ -1206,6 +1206,9 @@ struct X86CPU { /* if true fill the top bits of the MTRR_PHYSMASKn variable range */ bool fill_mtrr_mask; + /* if true override the phys_bits value with a value read from the host */ + bool host_phys_bits; + /* Number of physical address bits supported */ uint32_t phys_bits; |