diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c index 1102b00ecb..662e7e85bb 100644 --- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c +++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c @@ -646,16 +646,19 @@ PlatformAddressWidthFromCpuid ( )); if (Valid) { - if (PhysBits > 47) { + if (PhysBits > 46) { /* * Avoid 5-level paging altogether for now, which limits * PhysBits to 48. Also avoid using address bit 48, due to sign * extension we can't identity-map these addresses (and lots of * places in edk2 assume we have everything identity-mapped). * So the actual limit is 47. + * + * Also some older linux kernels apparently have problems handling + * phys-bits > 46 correctly, so use that as limit. */ - DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 47 (avoid 5-level paging)\n", __func__)); - PhysBits = 47; + DEBUG ((DEBUG_INFO, "%a: limit PhysBits to 46 (avoid 5-level paging)\n", __func__)); + PhysBits = 46; } if (!Page1GSupport && (PhysBits > 40)) {