diff options
Diffstat (limited to '')
| -rw-r--r-- | arch/x86/kvm/lapic.c | 25 |
1 files changed, 18 insertions, 7 deletions
diff --git a/arch/x86/kvm/lapic.c b/arch/x86/kvm/lapic.c index e542cf285b51..113ca9661ab2 100644 --- a/arch/x86/kvm/lapic.c +++ b/arch/x86/kvm/lapic.c @@ -51,11 +51,6 @@ #define mod_64(x, y) ((x) % (y)) #endif -#define PRId64 "d" -#define PRIx64 "llx" -#define PRIu64 "u" -#define PRIo64 "o" - /* 14 is the version for Xeon and Pentium 8.4.8*/ #define APIC_VERSION 0x14UL #define LAPIC_MMIO_LENGTH (1 << 12) @@ -229,6 +224,23 @@ static int kvm_recalculate_phys_map(struct kvm_apic_map *new, u32 physical_id; /* + * For simplicity, KVM always allocates enough space for all possible + * xAPIC IDs. Yell, but don't kill the VM, as KVM can continue on + * without the optimized map. + */ + if (WARN_ON_ONCE(xapic_id > new->max_apic_id)) + return -EINVAL; + + /* + * Bail if a vCPU was added and/or enabled its APIC between allocating + * the map and doing the actual calculations for the map. Note, KVM + * hardcodes the x2APIC ID to vcpu_id, i.e. there's no TOCTOU bug if + * the compiler decides to reload x2apic_id after this check. + */ + if (x2apic_id > new->max_apic_id) + return -E2BIG; + + /* * Deliberately truncate the vCPU ID when detecting a mismatched APIC * ID to avoid false positives if the vCPU ID, i.e. x2APIC ID, is a * 32-bit value. Any unwanted aliasing due to truncation results will @@ -253,8 +265,7 @@ static int kvm_recalculate_phys_map(struct kvm_apic_map *new, */ if (vcpu->kvm->arch.x2apic_format) { /* See also kvm_apic_match_physical_addr(). */ - if ((apic_x2apic_mode(apic) || x2apic_id > 0xff) && - x2apic_id <= new->max_apic_id) + if (apic_x2apic_mode(apic) || x2apic_id > 0xff) new->phys_map[x2apic_id] = apic; if (!apic_x2apic_mode(apic) && !new->phys_map[xapic_id]) |