[PATCH v3 0/3] OvmfPkg/PlatformPei: prefer etc/e820 for memory detection

[PATCH v3 0/3] OvmfPkg/PlatformPei: prefer etc/e820 for memory detection

[Gerd Hoffmann]

Don't use cmos for memory detection if possible.
qemu provides the etc/e820 firmware config file
as alternative since 2013.

v2:
 - fix lowmem detection.
 - pick up review tags.
 - add rfc patch to completely drop cmos support.

v3:
 - fix CI failure.

Gerd Hoffmann (3):
  OvmfPkg/PlatformPei: ScanOrAdd64BitE820Ram improvements
  OvmfPkg/PlatformPei: prefer etc/e820 for memory detection
  RFC: OvmfPkg/PlatformPei: stop using cmos for memory detection

 OvmfPkg/PlatformPei/MemDetect.c | 84 +++++++++++----------------------
 1 file changed, 28 insertions(+), 56 deletions(-)

-- 
2.31.1

[PATCH v3 1/3] OvmfPkg/PlatformPei: ScanOrAdd64BitE820Ram improvements

[Gerd Hoffmann]

Add a bool parameter to ScanOrAdd64BitE820Ram to explicitly specify
whenever ScanOrAdd64BitE820Ram should add HOBs for high memory (above
4G) or scan only.

Also add a lowmem parameter so ScanOrAdd64BitE820Ram
can report the memory size below 4G.

This allows a more flexible usage of ScanOrAdd64BitE820Ram,
a followup patch will use it for all memory detection.

No functional change.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3593
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
---
 OvmfPkg/PlatformPei/MemDetect.c | 28 +++++++++++++++++++++-------
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/OvmfPkg/PlatformPei/MemDetect.c b/OvmfPkg/PlatformPei/MemDetect.c
index 2c2c4641ec8a..500c1d4d5231 100644
--- a/OvmfPkg/PlatformPei/MemDetect.c
+++ b/OvmfPkg/PlatformPei/MemDetect.c
@@ -200,6 +200,8 @@ QemuUc32BaseInitialization (
 STATIC
 EFI_STATUS
 ScanOrAdd64BitE820Ram (
+  IN BOOLEAN AddHighHob,
+  OUT UINT64 *LowMemory OPTIONAL,
   OUT UINT64 *MaxAddress OPTIONAL
   )
 {
@@ -217,6 +219,9 @@ ScanOrAdd64BitE820Ram (
     return EFI_PROTOCOL_ERROR;
   }
 
+  if (LowMemory != NULL) {
+    *LowMemory = 0;
+  }
   if (MaxAddress != NULL) {
     *MaxAddress = BASE_4GB;
   }
@@ -232,9 +237,8 @@ ScanOrAdd64BitE820Ram (
       E820Entry.Length,
       E820Entry.Type
       ));
-    if (E820Entry.Type == EfiAcpiAddressRangeMemory &&
-        E820Entry.BaseAddr >= BASE_4GB) {
-      if (MaxAddress == NULL) {
+    if (E820Entry.Type == EfiAcpiAddressRangeMemory) {
+      if (AddHighHob && E820Entry.BaseAddr >= BASE_4GB) {
         UINT64 Base;
         UINT64 End;
 
@@ -254,11 +258,12 @@ ScanOrAdd64BitE820Ram (
             End
             ));
         }
-      } else {
+      }
+      if (MaxAddress || LowMemory) {
         UINT64 Candidate;
 
         Candidate = E820Entry.BaseAddr + E820Entry.Length;
-        if (Candidate > *MaxAddress) {
+        if (MaxAddress && Candidate > *MaxAddress) {
           *MaxAddress = Candidate;
           DEBUG ((
             DEBUG_VERBOSE,
@@ -267,6 +272,15 @@ ScanOrAdd64BitE820Ram (
             *MaxAddress
             ));
         }
+        if (LowMemory && Candidate > *LowMemory && Candidate < BASE_4GB) {
+          *LowMemory = Candidate;
+          DEBUG ((
+            DEBUG_VERBOSE,
+            "%a: LowMemory=0x%Lx\n",
+            __FUNCTION__,
+            *LowMemory
+            ));
+        }
       }
     }
   }
@@ -353,7 +367,7 @@ GetFirstNonAddress (
   // Otherwise, get the flat size of the memory above 4GB from the CMOS (which
   // can only express a size smaller than 1TB), and add it to 4GB.
   //
-  Status = ScanOrAdd64BitE820Ram (&FirstNonAddress);
+  Status = ScanOrAdd64BitE820Ram (FALSE, NULL, &FirstNonAddress);
   if (EFI_ERROR (Status)) {
     FirstNonAddress = BASE_4GB + GetSystemMemorySizeAbove4gb ();
   }
@@ -754,7 +768,7 @@ QemuInitializeRam (
     // entries. Otherwise, create a single memory HOB with the flat >=4GB
     // memory size read from the CMOS.
     //
-    Status = ScanOrAdd64BitE820Ram (NULL);
+    Status = ScanOrAdd64BitE820Ram (TRUE, NULL, NULL);
     if (EFI_ERROR (Status) && UpperMemorySize != 0) {
       AddMemoryBaseSizeHob (BASE_4GB, UpperMemorySize);
     }
-- 
2.31.1

[PATCH v3 2/3] OvmfPkg/PlatformPei: prefer etc/e820 for memory detection

[Gerd Hoffmann]

Prefer the e820 map provided via qemu firmware config interface
for memory detection.  Use rtc cmos only as fallback, which should
be rarely needed these days as qemu supports etc/e820 since 2013.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3593
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Philippe Mathieu-Daude <philmd@redhat.com>
---
 OvmfPkg/PlatformPei/MemDetect.c | 15 ++++++++++++---
 1 file changed, 12 insertions(+), 3 deletions(-)

diff --git a/OvmfPkg/PlatformPei/MemDetect.c b/OvmfPkg/PlatformPei/MemDetect.c
index 500c1d4d5231..1d942b12d519 100644
--- a/OvmfPkg/PlatformPei/MemDetect.c
+++ b/OvmfPkg/PlatformPei/MemDetect.c
@@ -293,9 +293,16 @@ GetSystemMemorySizeBelow4gb (
   VOID
   )
 {
+  EFI_STATUS Status;
+  UINT64 LowerMemorySize = 0;
   UINT8 Cmos0x34;
   UINT8 Cmos0x35;
 
+  Status = ScanOrAdd64BitE820Ram (FALSE, &LowerMemorySize, NULL);
+  if (Status == EFI_SUCCESS && LowerMemorySize > 0) {
+    return (UINT32)LowerMemorySize;
+  }
+
   //
   // CMOS 0x34/0x35 specifies the system memory above 16 MB.
   // * CMOS(0x35) is the high byte
@@ -722,7 +729,6 @@ QemuInitializeRam (
   // Determine total memory size available
   //
   LowerMemorySize = GetSystemMemorySizeBelow4gb ();
-  UpperMemorySize = GetSystemMemorySizeAbove4gb ();
 
   if (mBootMode == BOOT_ON_S3_RESUME) {
     //
@@ -769,8 +775,11 @@ QemuInitializeRam (
     // memory size read from the CMOS.
     //
     Status = ScanOrAdd64BitE820Ram (TRUE, NULL, NULL);
-    if (EFI_ERROR (Status) && UpperMemorySize != 0) {
-      AddMemoryBaseSizeHob (BASE_4GB, UpperMemorySize);
+    if (EFI_ERROR (Status)) {
+      UpperMemorySize = GetSystemMemorySizeAbove4gb ();
+      if (UpperMemorySize != 0) {
+        AddMemoryBaseSizeHob (BASE_4GB, UpperMemorySize);
+      }
     }
   }
 
-- 
2.31.1

[PATCH v3 3/3] RFC: OvmfPkg/PlatformPei: stop using cmos for memory detection

[Gerd Hoffmann]

Not needed for qemu 1.7 (released in 2013) and newer.

Ref: https://bugzilla.tianocore.org/show_bug.cgi?id=3593
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
---
 OvmfPkg/PlatformPei/MemDetect.c | 59 +++------------------------------
 1 file changed, 4 insertions(+), 55 deletions(-)

diff --git a/OvmfPkg/PlatformPei/MemDetect.c b/OvmfPkg/PlatformPei/MemDetect.c
index 1d942b12d519..778d150e956b 100644
--- a/OvmfPkg/PlatformPei/MemDetect.c
+++ b/OvmfPkg/PlatformPei/MemDetect.c
@@ -37,7 +37,6 @@ Module Name:
 #include <Library/QemuFwCfgSimpleParserLib.h>
 
 #include "Platform.h"
-#include "Cmos.h"
 
 UINT8 mPhysMemAddressWidth;
 
@@ -295,52 +294,12 @@ GetSystemMemorySizeBelow4gb (
 {
   EFI_STATUS Status;
   UINT64 LowerMemorySize = 0;
-  UINT8 Cmos0x34;
-  UINT8 Cmos0x35;
 
   Status = ScanOrAdd64BitE820Ram (FALSE, &LowerMemorySize, NULL);
-  if (Status == EFI_SUCCESS && LowerMemorySize > 0) {
-    return (UINT32)LowerMemorySize;
-  }
+  ASSERT_EFI_ERROR (Status);
+  ASSERT (LowerMemorySize > 0);
+  return (UINT32)LowerMemorySize;
 
-  //
-  // CMOS 0x34/0x35 specifies the system memory above 16 MB.
-  // * CMOS(0x35) is the high byte
-  // * CMOS(0x34) is the low byte
-  // * The size is specified in 64kb chunks
-  // * Since this is memory above 16MB, the 16MB must be added
-  //   into the calculation to get the total memory size.
-  //
-
-  Cmos0x34 = (UINT8) CmosRead8 (0x34);
-  Cmos0x35 = (UINT8) CmosRead8 (0x35);
-
-  return (UINT32) (((UINTN)((Cmos0x35 << 8) + Cmos0x34) << 16) + SIZE_16MB);
-}
-
-
-STATIC
-UINT64
-GetSystemMemorySizeAbove4gb (
-  )
-{
-  UINT32 Size;
-  UINTN  CmosIndex;
-
-  //
-  // CMOS 0x5b-0x5d specifies the system memory above 4GB MB.
-  // * CMOS(0x5d) is the most significant size byte
-  // * CMOS(0x5c) is the middle size byte
-  // * CMOS(0x5b) is the least significant size byte
-  // * The size is specified in 64kb chunks
-  //
-
-  Size = 0;
-  for (CmosIndex = 0x5d; CmosIndex >= 0x5b; CmosIndex--) {
-    Size = (UINT32) (Size << 8) + (UINT32) CmosRead8 (CmosIndex);
-  }
-
-  return LShiftU64 (Size, 16);
 }
 
 
@@ -371,12 +330,9 @@ GetFirstNonAddress (
   // If QEMU presents an E820 map, then get the highest exclusive >=4GB RAM
   // address from it. This can express an address >= 4GB+1TB.
   //
-  // Otherwise, get the flat size of the memory above 4GB from the CMOS (which
-  // can only express a size smaller than 1TB), and add it to 4GB.
-  //
   Status = ScanOrAdd64BitE820Ram (FALSE, NULL, &FirstNonAddress);
   if (EFI_ERROR (Status)) {
-    FirstNonAddress = BASE_4GB + GetSystemMemorySizeAbove4gb ();
+    FirstNonAddress = BASE_4GB;
   }
 
   //
@@ -719,7 +675,6 @@ QemuInitializeRam (
   )
 {
   UINT64                      LowerMemorySize;
-  UINT64                      UpperMemorySize;
   MTRR_SETTINGS               MtrrSettings;
   EFI_STATUS                  Status;
 
@@ -775,12 +730,6 @@ QemuInitializeRam (
     // memory size read from the CMOS.
     //
     Status = ScanOrAdd64BitE820Ram (TRUE, NULL, NULL);
-    if (EFI_ERROR (Status)) {
-      UpperMemorySize = GetSystemMemorySizeAbove4gb ();
-      if (UpperMemorySize != 0) {
-        AddMemoryBaseSizeHob (BASE_4GB, UpperMemorySize);
-      }
-    }
   }
 
   //
-- 
2.31.1