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| author | Gerd Hoffmann <kraxel@redhat.com> | 2024-03-01 11:23:58 +0100 |
|---|---|---|
| committer | mergify[bot] <37929162+mergify[bot]@users.noreply.github.com> | 2024-06-06 09:06:28 +0000 |
| commit | 603ad2d6ae7c0b46815123a59a2b8c8169711c0e (patch) | |
| tree | f0fa44b4a0b2bb749840e6749f8b67ef31f75681 | |
| parent | 65b0d08786888284cd1bb705c58f53a65ae443b0 (diff) | |
| download | edk2-603ad2d6ae7c0b46815123a59a2b8c8169711c0e.zip edk2-603ad2d6ae7c0b46815123a59a2b8c8169711c0e.tar.gz edk2-603ad2d6ae7c0b46815123a59a2b8c8169711c0e.tar.bz2 | |
OvmfPkg/PlatformInitLib: add support for GuestPhysBits
Add support for GuestPhysBits (cpuid 0x80000008, eax, bits 23:16).
GuestPhysBits is a field which can be set by the hypervisor to inform
the guest about the /usable/ physical address space bits. This can be
smaller than the PhysBits of the CPU, for example because of nested
paging limitations.
OVMF will read GuestPhysBits, log the value, in case it is set use it
as upper limit.
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
| -rw-r--r-- | OvmfPkg/Library/PlatformInitLib/MemDetect.c | 17 |
1 files changed, 14 insertions, 3 deletions
diff --git a/OvmfPkg/Library/PlatformInitLib/MemDetect.c b/OvmfPkg/Library/PlatformInitLib/MemDetect.c index e64c0ee..f531b98 100644 --- a/OvmfPkg/Library/PlatformInitLib/MemDetect.c +++ b/OvmfPkg/Library/PlatformInitLib/MemDetect.c @@ -633,6 +633,7 @@ PlatformAddressWidthFromCpuid ( {
UINT32 RegEax, RegEbx, RegEcx, RegEdx, Max;
UINT8 PhysBits;
+ UINT8 GuestPhysBits;
CHAR8 Signature[13];
IA32_CR4 Cr4;
BOOLEAN Valid = FALSE;
@@ -655,13 +656,17 @@ PlatformAddressWidthFromCpuid ( if (Max >= 0x80000008) {
AsmCpuid (0x80000008, &RegEax, NULL, NULL, NULL);
- PhysBits = (UINT8)RegEax;
+ PhysBits = (UINT8)RegEax;
+ GuestPhysBits = (UINT8)(RegEax >> 16);
} else {
- PhysBits = 36;
+ PhysBits = 36;
+ GuestPhysBits = 0;
}
if (!QemuQuirk) {
Valid = TRUE;
+ } else if (GuestPhysBits) {
+ Valid = TRUE;
} else if (PhysBits >= 41) {
Valid = TRUE;
} else if (AsciiStrCmp (Signature, "GenuineIntel") == 0) {
@@ -678,15 +683,21 @@ PlatformAddressWidthFromCpuid ( DEBUG ((
DEBUG_INFO,
- "%a: Signature: '%a', PhysBits: %d, QemuQuirk: %a, la57: %a, Valid: %a\n",
+ "%a: Signature: '%a', PhysBits: %d, GuestPhysBits: %d, QemuQuirk: %a, la57: %a, Valid: %a\n",
__func__,
Signature,
PhysBits,
+ GuestPhysBits,
QemuQuirk ? "On" : "Off",
Cr4.Bits.LA57 ? "On" : "Off",
Valid ? "Yes" : "No"
));
+ if (GuestPhysBits && (PhysBits > GuestPhysBits)) {
+ DEBUG ((DEBUG_INFO, "%a: limit PhysBits to %d (GuestPhysBits)\n", __func__, GuestPhysBits));
+ PhysBits = GuestPhysBits;
+ }
+
if (Valid) {
/*
* Due to the sign extension we can use only the lower half of the
|