diff options
Diffstat (limited to 'OvmfPkg')
| -rw-r--r-- | OvmfPkg/Library/PlatformInitLib/MemDetect.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c index f531b98..2b6404c 100644 --- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c +++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c @@ -706,7 +706,7 @@ PlatformAddressWidthFromCpuid ( * and a 56 bit wide address space with 5 paging levels.
*/
if (Cr4.Bits.LA57) {
- if (PhysBits > 48) {
+ if ((PhysBits > 48) && !GuestPhysBits) {
/*
* Some Intel CPUs support 5-level paging, have more than 48
* phys-bits but support only 4-level EPT, which effectively
@@ -716,11 +716,11 @@ PlatformAddressWidthFromCpuid ( * problem: They can handle guest phys-bits larger than 48
* only in case the host runs in 5-level paging mode.
*
- * Until we have some way to communicate that kind of
- * limitations from hypervisor to guest, limit phys-bits
- * to 48 unconditionally.
+ * GuestPhysBits is used to communicate that kind of
+ * limitations from hypervisor to guest. If GuestPhysBits is
+ * not set play safe and limit phys-bits to 48.
*/
- DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 48 (5-level paging)\n", __func__));
+ DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 48 (5-level paging, no GuestPhysBits)\n", __func__));
PhysBits = 48;
}
} else {
|