Add lesson 27

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+Let's try to get information from one of the system tables that we've discovered.
+
+You can find the most recent version of the "System Management BIOS (SMBIOS) Reference Specification" on the DMTF site https://www.dmtf.org/dsp/DSP0134
+For example now 3.4.0 is the most recent version https://www.dmtf.org/sites/default/files/standards/documents/DSP0134_3.4.0.pdf
+
+From the previous lesson we now, that SMBIOS table is declared under `gEfiSmbiosTableGuid`.
+
+Let's create an app, that would print the address of this table.
+```
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+#include <Library/BaseMemoryLib.h>
+
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  for (UINTN i=0; i<SystemTable->NumberOfTableEntries; i++) {
+    if (CompareGuid(&(SystemTable->ConfigurationTable[i].VendorGuid), &gEfiSmbiosTableGuid)) {
+      Print(L"SMBIOS table is placed at %p\n", SystemTable->ConfigurationTable[i].VendorTable);
+    }
+  }
+  return EFI_SUCCESS;
+}
+```
+
+In this code we've used `CompareGuid` function from the https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Library/BaseMemoryLib.h:
+```
+/**
+  Compares two GUIDs.
+  This function compares Guid1 to Guid2.  If the GUIDs are identical then TRUE is returned.
+  If there are any bit differences in the two GUIDs, then FALSE is returned.
+  If Guid1 is NULL, then ASSERT().
+  If Guid2 is NULL, then ASSERT().
+  @param  Guid1       A pointer to a 128 bit GUID.
+  @param  Guid2       A pointer to a 128 bit GUID.
+  @retval TRUE        Guid1 and Guid2 are identical.
+  @retval FALSE       Guid1 and Guid2 are not identical.
+**/
+BOOLEAN
+EFIAPI
+CompareGuid (
+  IN CONST GUID  *Guid1,
+  IN CONST GUID  *Guid2
+  );
+```
+
+Don't forget to add:
+```
+[Guids]
+  gEfiSmbiosTableGuid
+```
+to app *inf file.
+
+Let's build our app and execute it under OVMF:
+```
+FS0:\> SmbiosInfo.efi
+SMBIOS table is placed at 7941000
+```
+
+# Get SMBIOS tables with `dmem`
+
+UEFI shell has a command `dmem` for memory dump:
+```
+FS0:\> dmem -? -b
+Displays the contents of system or device memory.
+
+DMEM [-b] [address] [size] [-MMIO]
+
+  -b      - Displays one screen at a time.
+  -MMIO   - Forces address cycles to the PCI bus.
+  address - Specifies a starting address in hexadecimal format.
+  size    - Specifies the number of bytes to display in hexadecimal format.
+
+NOTES:
+  1. This command displays the contents of system memory or device memory.
+  2. Enter address and size in hexadecimal format.
+  3. If address is not specified, the contents of the UEFI System Table
+     are displayed. Otherwise, memory starting at the specified address is displayed.
+  4. Size specifies the number of bytes to display. If size is not specified,
+     512 bytes are displayed.
+  5. If MMIO is not specified, main system memory is displayed. Otherwise,
+     device memory is displayed through the use of the
+     EFI_PCI_ROOT_BRIDGE_IO_PROTOCOL.
+
+EXAMPLES:
+  * To display the UEFI system table pointer entries:
+    fs0:\> dmem
+
+  * To display memory contents from 1af3088 with size of 16 bytes:
+    Shell> dmem 1af3088 16
+
+  * To display memory mapped IO contents from 1af3088 with a size of 16 bytes:
+    Shell> dmem 1af3088 16 -MMIO
+```
+
+Let's use it to print 0x30 bytes from the 0x7941000 address that we count as a SMBIOS table pointer.
+```
+FS0:\> dmem 7941000 30
+Memory Address 0000000007941000 30 Bytes
+  07941000: 5F 53 4D 5F 26 1F 02 08-53 00 00 00 00 00 00 00  *_SM_&...S.......*
+  07941010: 5F 44 4D 49 5F 0A 91 01-00 00 94 07 09 00 28 AF  *_DMI_.........(.*
+  07941020: AF AF AF AF AF AF AF AF-AF AF AF AF AF AF AF AF  *................*
+```
+
+If you look at SMBIOS specification for SMBIOS Entry Point structure you'll see, that `_SM_` and `_DMI_` are predefined values in this structure.
+
+![SMBIOS_entry_structure](SMBIOS_entry_structure.png?raw=true "SMBIOS_entry_structure")
+
+You can find definition for the structure itself in edk2 under https://github.com/tianocore/edk2/blob/master/MdePkg/Include/IndustryStandard/SmBios.h
+```
+typedef struct {
+  UINT8   AnchorString[4];
+  UINT8   EntryPointStructureChecksum;
+  UINT8   EntryPointLength;
+  UINT8   MajorVersion;
+  UINT8   MinorVersion;
+  UINT16  MaxStructureSize;
+  UINT8   EntryPointRevision;
+  UINT8   FormattedArea[5];
+  UINT8   IntermediateAnchorString[5];
+  UINT8   IntermediateChecksum;
+  UINT16  TableLength;
+  UINT32  TableAddress;
+  UINT16  NumberOfSmbiosStructures;
+  UINT8   SmbiosBcdRevision;
+} SMBIOS_TABLE_ENTRY_POINT;
+```
+
+If you calculate offsets for different fields you can parse memory dump:
+
+![SMBIOS_entry_structure_dump](SMBIOS_entry_structure_dump.png?raw=true "SMBIOS_entry_structure_dump")
+
+System has 9 SMBIOS structures placed from 0x07940000 to (0x07940000+0x191).
+
+Now when we know address for SMBIOS structures, we can dump them as well.
+```
+FS0:\> dmem 07940000 191
+Memory Address 0000000007940000 191 Bytes
+  07940000: 01 1B 00 01 01 02 03 00-00 00 00 00 00 00 00 00  *................*
+  07940010: 00 00 00 00 00 00 00 00-06 00 00 51 45 4D 55 00  *...........QEMU.*
+  07940020: 53 74 61 6E 64 61 72 64-20 50 43 20 28 69 34 34  *Standard PC (i44*
+  07940030: 30 46 58 20 2B 20 50 49-49 58 2C 20 31 39 39 36  *0FX + PIIX, 1996*
+  07940040: 29 00 70 63 2D 69 34 34-30 66 78 2D 66 6F 63 61  *).pc-i440fx-foca*
+  07940050: 6C 00 00 03 16 00 03 01-01 02 00 00 03 03 03 02  *l...............*
+  07940060: 00 00 00 00 00 00 00 00-00 51 45 4D 55 00 70 63  *.........QEMU.pc*
+  07940070: 2D 69 34 34 30 66 78 2D-66 6F 63 61 6C 00 00 04  *-i440fx-focal...*
+  07940080: 2A 00 04 01 03 01 02 63-06 00 00 FD FB 8B 07 03  **......c........*
+  07940090: 00 00 00 D0 07 D0 07 41-01 FF FF FF FF FF FF 00  *.......A........*
+  079400A0: 00 00 01 01 01 02 00 01-00 43 50 55 20 30 00 51  *.........CPU 0.Q*
+  079400B0: 45 4D 55 00 70 63 2D 69-34 34 30 66 78 2D 66 6F  *EMU.pc-i440fx-fo*
+  079400C0: 63 61 6C 00 00 10 17 00-10 01 03 06 00 00 02 00  *cal.............*
+  079400D0: FE FF 01 00 00 00 00 00-00 00 00 00 00 00 11 28  *...............(*
+  079400E0: 00 11 00 10 FE FF FF FF-FF FF 80 00 09 00 01 00  *................*
+  079400F0: 07 02 00 00 00 02 00 00-00 00 00 00 00 00 00 00  *................*
+  07940100: 00 00 00 00 00 00 44 49-4D 4D 20 30 00 51 45 4D  *......DIMM 0.QEM*
+  07940110: 55 00 00 13 1F 00 13 00-00 00 00 FF FF 01 00 00  *U...............*
+  07940120: 10 01 00 00 00 00 00 00-00 00 00 00 00 00 00 00  *................*
+  07940130: 00 00 00 00 20 0B 00 20-00 00 00 00 00 00 00 00  *.... .. ........*
+  07940140: 00 00 1A 00 00 01 02 00-E8 03 00 08 00 00 00 00  *................*
+  07940150: 00 00 00 00 1C 00 00 FF-FF 00 00 45 46 49 20 44  *...........EFI D*
+  07940160: 65 76 65 6C 6F 70 6D 65-6E 74 20 4B 69 74 20 49  *evelopment Kit I*
+  07940170: 49 20 2F 20 4F 56 4D 46-00 30 2E 30 2E 30 00 30  *I / OVMF.0.0.0.0*
+  07940180: 32 2F 30 36 2F 32 30 31-35 00 00 7F 04 FF FE 00  *2/06/2015.......*
+  07940190: 00                                               *.*
+```
+
+# Use EFI_SMBIOS_PROTOCOL to parse SMBIOS data
+
+We can use direct pointer arithmetics to parse SMBIOS tables, but that would be very tedious.
+
+Luckily UEFI PI specification defines a `EFI_SMBIOS_PROTOCOL`, that we can use to get SMBIOS data.
+
+```
+EFI_SMBIOS_PROTOCOL
+
+Summary:
+Allows consumers to log SMBIOS data records, and enables the producer to create the SMBIOS tables for a platform.
+
+Protocol Interface Structure:
+typedef struct _EFI_SMBIOS_PROTOCOL {
+ EFI_SMBIOS_ADD Add;
+ EFI_SMBIOS_UPDATE_STRINGUpdateString;
+ EFI_SMBIOS_REMOVE Remove;
+ EFI_SMBIOS_GET_NEXT GetNext;
+ UINT8 MajorVersion;
+ UINT8 MinorVersion;
+} EFI_SMBIOS_PROTOCOL;
+
+Member Description:
+Add		Add an SMBIOS record including the formatted area and the optional strings
+		that follow the formatted area.
+UpdateString 	Update a string in the SMBIOS record.
+Remove		Remove an SMBIOS record.
+GetNext		Discover all SMBIOS records.
+MajorVersion	The major revision of the SMBIOS specification supported.
+MinorVersion	The minor revision of the SMBIOS specification supported.
+
+Description:
+This protocol provides an interface to add, remove or discover SMBIOS records. The driver which
+produces this protocol is responsible for creating the SMBIOS data tables and installing the pointer
+to the tables in the EFI System Configuration Table.
+```
+
+Right now we are interested in SMBIOS table parsing, so we need to utilize `GetNext` function:
+```
+EFI_SMBIOS_PROTOCOL.GetNext()
+
+Summary:
+Allow the caller to discover all or some of the SMBIOS records.
+Prototype
+typedef
+EFI_STATUS
+(EFIAPI *EFI_SMBIOS_GET_NEXT) (
+ IN CONST EFI_SMBIOS_PROTOCOL *This,
+ IN OUT EFI_SMBIOS_HANDLE *SmbiosHandle,
+ IN EFI_SMBIOS_TYPE *Type, OPTIONAL
+ OUT EFI_SMBIOS_TABLE_HEADER **Record,
+ OUT EFI_HANDLE *ProducerHandle OPTIONAL
+ );
+
+Parameters:
+This		The EFI_SMBIOS_PROTOCOL instance.
+SmbiosHandle	On entry, points to the previous handle of the SMBIOS record. On exit, points to the
+		next SMBIOS record handle. If it is FFFEh on entry, then the first SMBIOS record
+		handle will be returned. If it returns FFFEh on exit, then there are no more SMBIOS
+		records.
+Type		On entry, it points to the type of the next SMBIOS record to return. If NULL, it
+		indicates that the next record of any type will be returned. Type is not modified by
+		the this function.
+Record		On exit, points to a pointer to the the SMBIOS Record consisting of the formatted area
+		followed by the unformatted area. The unformatted area optionally contains text
+		strings.
+ProducerHandle	On exit, points to the ProducerHandle registered by Add(). If no
+		ProducerHandle was passed into Add() NULL is returned. If a NULL pointer is
+		passed in no data will be returned
+
+Description
+This function allows all of the SMBIOS records to be discovered. It's possible to find
+only the SMBIOS records that match the optional Type argument.
+
+Status Codes Returned:
+EFI_SUCCESS 	.SMBIOS record information was successfully returned in Record.
+		SmbiosHandle is the handle of the current SMBIOS record
+EFI_NOT_FOUND 	The SMBIOS record with SmbiosHandle was the last available record.
+```
+
+First let's get this protocol in our app.
+```
+EFI_SMBIOS_PROTOCOL* SmbiosProtocol;
+EFI_STATUS Status = gBS->LocateProtocol (
+                &gEfiSmbiosProtocolGuid,
+                NULL,
+                (VOID**)&SmbiosProtocol
+                );
+if (EFI_ERROR (Status)) {
+  return Status;
+}
+```
+To use it we need to add include to our app https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Protocol/Smbios.h:
+```
+#include <Protocol/Smbios.h>
+```
+And add protocol guid to our *.inf file:
+```
+[Protocols]
+  gEfiSmbiosProtocolGuid
+```
+
+Now let's try to get SMBIOS tables. We would be using `SMBIOS_HANDLE_PI_RESERVED` as `EFI_SMBIOS_HANDLE` in protocol calls. You can find explanation in https://github.com/tianocore/edk2/blob/master/MdePkg/Include/IndustryStandard/SmBios.h:
+```
+///
+/// Reference SMBIOS 2.7, chapter 6.1.2.
+/// The UEFI Platform Initialization Specification reserves handle number FFFEh for its
+/// EFI_SMBIOS_PROTOCOL.Add() function to mean "assign an unused handle number automatically."
+/// This number is not used for any other purpose by the SMBIOS specification.
+///
+#define SMBIOS_HANDLE_PI_RESERVED 0xFFFE
+```
+
+Also before we start writing code look at the definition of `EFI_SMBIOS_TABLE_HEADER` structure, that we would receive on `GetNext` calls.
+https://github.com/tianocore/edk2/blob/master/MdePkg/Include/Protocol/Smbios.h
+```
+typedef SMBIOS_STRUCTURE    EFI_SMBIOS_TABLE_HEADER;
+```
+https://github.com/tianocore/edk2/blob/master/MdePkg/Include/IndustryStandard/SmBios.h
+```
+///
+/// The Smbios structure header.
+///
+typedef struct {
+  SMBIOS_TYPE    Type;
+  UINT8          Length;
+  SMBIOS_HANDLE  Handle;
+} SMBIOS_STRUCTURE;
+```
+
+Now we are ready to write some code. Write a code to print all types of Smbios tables that are present in the system:
+```
+EFI_SMBIOS_HANDLE SmbiosHandle = SMBIOS_HANDLE_PI_RESERVED;
+EFI_SMBIOS_TABLE_HEADER* Record;
+Status = SmbiosProtocol->GetNext(SmbiosProtocol,
+                                 &SmbiosHandle,
+                                 NULL,
+                                 &Record,
+                                 NULL);
+while (!EFI_ERROR(Status)) {
+  Print (L"SMBIOS Type %d \n", Record->Type);
+  Status = SmbiosProtocol->GetNext(SmbiosProtocol,
+                                   &SmbiosHandle,
+                                   NULL,
+                                   &Record,
+                                   NULL);
+}
+```
+
+If you build our app and test it under OVMF you would get:
+```
+SMBIOS table is placed at 7941000
+SMBIOS Type 1
+SMBIOS Type 3
+SMBIOS Type 4
+SMBIOS Type 16
+SMBIOS Type 17
+SMBIOS Type 19
+SMBIOS Type 32
+SMBIOS Type 0
+```
+
+Ok, now let's write code that can parse information in these tables.
+
+Let's start with Type 0 table. edk2 has a structure description at https://github.com/tianocore/edk2/blob/master/MdePkg/Include/IndustryStandard/SmBios.h:
+```
+///
+/// BIOS Information (Type 0).
+///
+typedef struct {
+  SMBIOS_STRUCTURE          Hdr;
+  SMBIOS_TABLE_STRING       Vendor;
+  SMBIOS_TABLE_STRING       BiosVersion;
+  UINT16                    BiosSegment;
+  SMBIOS_TABLE_STRING       BiosReleaseDate;
+  UINT8                     BiosSize;
+  MISC_BIOS_CHARACTERISTICS BiosCharacteristics;
+  UINT8                     BIOSCharacteristicsExtensionBytes[2];
+  UINT8                     SystemBiosMajorRelease;
+  UINT8                     SystemBiosMinorRelease;
+  UINT8                     EmbeddedControllerFirmwareMajorRelease;
+  UINT8                     EmbeddedControllerFirmwareMinorRelease;
+  //
+  // Add for smbios 3.1.0
+  //
+  EXTENDED_BIOS_ROM_SIZE    ExtendedBiosSize;
+} SMBIOS_TABLE_TYPE0;
+```
+
+In this structure `SMBIOS_STRUCTURE Hdr` is a mandatory field that is the same as `EFI_SMBIOS_TABLE_HEADER` that we receive from our protocol function call.
+
+Also `SMBIOS_TABLE_STRING` is just an UINT8 value that defines a string number in an ASCII string array that is placed directly after the structure.
+
+```
+///
+/// Text strings associated with a given SMBIOS structure are returned in the dmiStrucBuffer, appended directly after
+/// the formatted portion of the structure. This method of returning string information eliminates the need for
+/// application software to deal with pointers embedded in the SMBIOS structure. Each string is terminated with a null
+/// (00h) BYTE and the set of strings is terminated with an additional null (00h) BYTE. When the formatted portion of
+/// a SMBIOS structure references a string, it does so by specifying a non-zero string number within the structure's
+/// string-set. For example, if a string field contains 02h, it references the second string following the formatted portion
+/// of the SMBIOS structure. If a string field references no string, a null (0) is placed in that string field. If the
+/// formatted portion of the structure contains string-reference fields and all the string fields are set to 0 (no string
+/// references), the formatted section of the structure is followed by two null (00h) BYTES.
+///
+typedef UINT8 SMBIOS_TABLE_STRING;
+```
+
+So let's write a simple function that returns actual ASCII string from a `EFI_SMBIOS_TABLE_HEADER*` and a string number:
+```
+CHAR8* GetRecordString(EFI_SMBIOS_TABLE_HEADER* Record, UINTN number)
+{
+  if (!number)
+    return "";
+
+  CHAR8* String = (CHAR8*)Record + Record->Length;
+  UINTN i=1;
+  while (i < number) {
+    String = String + AsciiStrSize(String);
+    i++;
+  }
+  return String;
+}
+```
+Here we've used `AsciiStrSize` function that is defined in https://github.com/tianocore/edk2/blob/master/MdePkg/Library/BaseLib/String.c file.
+```
+/**
+  Returns the size of a Null-terminated ASCII string in bytes, including the
+  Null terminator.
+  This function returns the size, in bytes, of the Null-terminated ASCII string
+  specified by String.
+  If String is NULL, then ASSERT().
+  If PcdMaximumAsciiStringLength is not zero and String contains more than
+  PcdMaximumAsciiStringLength ASCII characters, not including the Null-terminator,
+  then ASSERT().
+  @param  String  A pointer to a Null-terminated ASCII string.
+  @return The size of String.
+**/
+UINTN
+EFIAPI
+AsciiStrSize (
+  IN      CONST CHAR8               *String
+  )
+```
+
+Now we have everything to write actual parsing code in our `while` loop:
+
+```
+while (!EFI_ERROR(Status)) {
+  Print (L"SMBIOS Type %d \n", Record->Type);
+  switch (Record->Type) {
+    case EFI_SMBIOS_TYPE_BIOS_INFORMATION: {
+      SMBIOS_TABLE_TYPE0* Type0Record = (SMBIOS_TABLE_TYPE0*) Record;
+      Print(L"\tVendor=%a\n", GetRecordString(Record, Type0Record->Vendor));
+      Print(L"\tBiosVersion=%a\n", GetRecordString(Record, Type0Record->BiosVersion));
+      Print(L"\tBiosReleaseDate=%a\n", GetRecordString(Record, Type0Record->BiosReleaseDate));
+      Print(L"\tBiosSegment=0x%x\n", Type0Record->BiosSegment);
+      Print(L"\tSystemBiosMajorRelease=0x%x\n", Type0Record->SystemBiosMajorRelease);
+      Print(L"\tSystemBiosMinorRelease=0x%x\n", Type0Record->SystemBiosMinorRelease);
+      break;
+    }
+    default:
+      Print(L"\tTODO: Parsing for this table is not ready yet\n");
+      break;
+  }
+  Status = SmbiosProtocol->GetNext(SmbiosProtocol,
+                                   &SmbiosHandle,
+                                   NULL,
+                                   &Record,
+                                   NULL);
+}
+```
+To print ASCII strings here we've used `%a` format code (https://github.com/tianocore/edk/blob/master/Foundation/Library/Pei/PeiLib/Print/Print.c).
+
+
+If you build and execute our app under OVMF you would get:
+```
+FS0:\> SmbiosInfo.efi
+SMBIOS table is placed at 7941000
+
+SMBIOS Type 1
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 3
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 4
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 16
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 17
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 19
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 32
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 0
+        Vendor=EFI Development Kit II / OVMF
+        BiosVersion=0.0.0
+        BiosReleaseDate=02/06/2015
+        BiosSegment=0xE800
+        SystemBiosMajorRelease=0x0
+        SystemBiosMinorRelease=0x0
+```
+
+If you look closely at `dmem` dump from earlier, you'll see that these are the exact strings that were actually present in memory.
+
+We can easily to add code to parse other SMBIOS tables.
+
+For example here is some parsing code for table type 1 structure:
+```
+case EFI_SMBIOS_TYPE_SYSTEM_INFORMATION: {
+  SMBIOS_TABLE_TYPE1* Type1Record = (SMBIOS_TABLE_TYPE1*) Record;
+  Print(L"\tManufacturer=%a\n", GetRecordString(Record, Type1Record->Manufacturer));
+  Print(L"\tProductName=%a\n", GetRecordString(Record, Type1Record->ProductName));
+  Print(L"\tVersion=%a\n", GetRecordString(Record, Type1Record->Version));
+  Print(L"\tSerialNumber=%a\n", GetRecordString(Record, Type1Record->SerialNumber));
+  Print(L"\tUUID=%g\n", Type1Record->Uuid);
+  Print(L"\tWakeUpType=%d\n", Type1Record->WakeUpType);
+  Print(L"\tSKUNumber=%a\n", GetRecordString(Record, Type1Record->SKUNumber));
+  Print(L"\tFamily=%a\n", GetRecordString(Record, Type1Record->Family));
+  break;
+}
+```
+Structure itself is:
+```
+typedef struct {
+  SMBIOS_STRUCTURE        Hdr;
+  SMBIOS_TABLE_STRING     Manufacturer;
+  SMBIOS_TABLE_STRING     ProductName;
+  SMBIOS_TABLE_STRING     Version;
+  SMBIOS_TABLE_STRING     SerialNumber;
+  GUID                    Uuid;
+  UINT8                   WakeUpType;           ///< The enumeration value from MISC_SYSTEM_WAKEUP_TYPE.
+  SMBIOS_TABLE_STRING     SKUNumber;
+  SMBIOS_TABLE_STRING     Family;
+} SMBIOS_TABLE_TYPE1;
+```
+
+Build and execute:
+```
+FS0:\> SmbiosInfo.efi
+SMBIOS table is placed at 7941000
+
+SMBIOS Type 1
+        Manufacturer=QEMU
+        ProductName=Standard PC (i440FX + PIIX, 1996)
+        Version=pc-i440fx-focal
+        SerialNumber=
+        UUID=00000000-0000-0000-0000-000000000000
+        WakeUpType=6
+        SKUNumber=
+        Family=
+SMBIOS Type 3
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 4
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 16
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 17
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 19
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 32
+        TODO: Parsing for this table is not ready yet
+SMBIOS Type 0
+        Vendor=EFI Development Kit II / OVMF
+        BiosVersion=0.0.0
+        BiosReleaseDate=02/06/2015
+        BiosSegment=0xE800
+        SystemBiosMajorRelease=0x0
+        SystemBiosMinorRelease=0x0
+```
+
+As you remember the same information that is present in these SMBIOS tables is present in the main BIOS menu:
+
+![BIOS_menu](BIOS_menu.png?raw=true "BIOS_menu")
+
+And in case you wonder where OVMF defines all these information for its SMBIOS structures, checkout https://github.com/tianocore/edk2/blob/master/OvmfPkg/SmbiosPlatformDxe/SmbiosPlatformDxe.c and implementation of a `EFI_SMBIOS_PROTOCOL` is placed here https://github.com/tianocore/edk2/blob/master/MdeModulePkg/Universal/SmbiosDxe/SmbiosDxe.c
+
+# `smbiosview` command
+
+We can use `EFI_SMBIOS_PROTOCOL` to parse SMBIOS table information, but actually if you just want to see SMBIOS information there is a better option.
+
+UEFI shell has a `smbiosview` command that does exactly what we need.
+
+You can checkout sources for this command here: https://github.com/tianocore/edk2/tree/master/ShellPkg/Library/UefiShellDebug1CommandsLib/SmbiosView
+
+First checkout help for this command:
+```
+FS0:\> smbiosview -?
+Displays SMBIOS information.
+
+SMBIOSVIEW [-t SmbiosType]|[-h SmbiosHandle]|[-s]|[-a]
+
+  -t            - Displays all structures of SmbiosType.
+  -h            - Displays structure of SmbiosHandle.
+  -s            - Displays a statistics table.
+  -a            - Displays all information.
+  SmbiosType    - Specifies a SMBIOS structure type.
+  SmbiosHandle  - Specifies a SMBIOS structure unique 16-bit handle.
+
+NOTES:
+  1. The SmbiosType parameter supports the following types:
+       0  - BIOS Information
+       1  - System Information
+       2  - Baseboard Information
+       3  - System Enclosure
+       4  - Processor Information
+       5  - Memory Controller Information
+       6  - Memory Module Information
+       7  - Cache Information
+       8  - Port Connector Information
+       9  - System Slots
+       10 - On Board Devices Information
+       11 - OEM Strings
+       12 - System Configuration Options
+       13 - BIOS Language Information
+       14 - Group Associations
+       15 - System Event Log
+       16 - Physical Memory Array
+       17 - Memory Device
+       18 - 32-bit Memory Error Information
+       19 - Memory Array Mapped Address
+       20 - Memory Device Mapped Address
+       21 - Built-in Pointing Device
+       22 - Portable Battery
+       23 - System Reset
+       24 - Hardware Security
+       25 - System Power Controls
+       26 - Voltage Probe
+       27 - Cooling Device
+       28 - Temperature Probe
+       29 - Electrical Current Probe
+       30 - Out-Of-Band Remote Access
+       31 - Boot Integrity Services (BIS) Entry Point
+       32 - System Boot Information
+       33 - 64-Bit Memory Error Information
+       34 - Management Device
+       35 - Management Device Component
+       36 - Management Device Threshold Data
+       37 - Memory Channel
+       38 - IPMI Device Information
+       39 - System Power Supply
+       40 - Additional Information
+       41 - Onboard Devices Extended Information
+       42 - Management Controller Host Interface
+       43 - TPM Device
+       44 - Processor Additional Information
+  2. Enter the SmbiosHandle parameter in hexadecimal format.
+     Do not use the '0x' prefix format for hexadecimal values.
+  3. Internal commands:
+       :q --------  quit smbiosview
+       :0 --------  Change smbiosview display NONE info
+       :1 --------  Change smbiosview display OUTLINE info
+       :2 --------  Change smbiosview display NORMAL info
+       :3 --------  Change smbiosview display DETAIL info
+       /? --------  Show help
+```
+
+Try to dump one of the structures that we've tried to parse manually:
+```
+FS0:\> smbiosview -t 0
+SMBIOS Entry Point Structure:
+Anchor String:        _SM_
+EPS Checksum:         0x26
+Entry Point Len:      31
+Version:              2.8
+Number of Structures: 9
+Max Struct size:      83
+Table Address:        0x7940000
+Table Length:         401
+Entry Point revision: 0x0
+SMBIOS BCD Revision:  0x28
+Inter Anchor:         _DMI_
+Inter Checksum:       0xA
+Formatted Area:
+  00000000: 00 00 00 00 00                                   *.....*
+
+=========================================================
+Query Structure, conditions are:
+QueryType   = 0
+QueryHandle = Random
+ShowType    = SHOW_DETAIL
+
+
+=========================================================
+Type=0, Handle=0x0
+Dump Structure as:
+Index=7,Length=0x4A,Addr=0x7940141
+00000000: 00 1A 00 00 01 02 00 E8-03 00 08 00 00 00 00 00  *................*
+FS0:\> 0: 00 00 00 1C 00 00 FF FF-00 00 45 46 49 20 44 65  *..........EFI De*
+00000020: 76 65 6C 6F 70 6D 65 6E-74 20 4B 69 74 20 49 49  *velopment Kit II*
+00000030: 20 2F 20 4F 56 4D 46 00-30 2E 30 2E 30 00 30 32  * / OVMF.0.0.0.02*
+00000040: 2F 30 36 2F 32 30 31 35-00 00                    */06/2015..*
+Structure Type: BIOS Information
+Format part Len : 26
+Structure Handle: 0
+Vendor: EFI Development Kit II / OVMF
+BiosVersion: 0.0.0
+BiosSegment: 0xE800
+BiosReleaseDate: 02/06/2015
+BiosSize:  64 KB
+BIOS Characteristics:
+BIOS Characteristics Not Supported
+ Bits 32:47 are reserved for BIOS Vendor
+ Bits 48:64 are reserved for System Vendor
+BIOS Characteristics Extension Byte1:
+BIOS Characteristics Extension Byte2:
+Enable Targeted Content Distribution
+UEFI Specification is supported
+The SMBIOS table describes a virtual machine
+ Bits 5:7 are reserved for future assignment
+SystemBiosMajorRelease: 0
+SystemBiosMinorRelease: 0
+EmbeddedControllerFirmwareMajorRelease: 255
+EmbeddedControllerFirmwareMinorRelease: 255
+```
+As you can see it is all the same info that we've received using `EFI_SMBIOS_PROTOCOL`.
+
+You can use this command to see what is inside all of the SMBIOS structures using:
+```
+FS0:\> smbiosview -b
+...
+```
+
+The output is too big to paste here, so check it out yourself!
diff --git a/Lesson_27/SMBIOS_entry_structure.png b/Lesson_27/SMBIOS_entry_structure.png
new file mode 100644
index 0000000..f488425
--- /dev/null
+++ b/Lesson_27/SMBIOS_entry_structure.png
diff --git a/Lesson_27/SMBIOS_entry_structure_dump.png b/Lesson_27/SMBIOS_entry_structure_dump.png
new file mode 100644
index 0000000..ff27b9b
--- /dev/null
+++ b/Lesson_27/SMBIOS_entry_structure_dump.png
diff --git a/Lesson_27/UefiLessonsPkg/SmbiosInfo/SmbiosInfo.c b/Lesson_27/UefiLessonsPkg/SmbiosInfo/SmbiosInfo.c
new file mode 100644
index 0000000..b75026d
--- /dev/null
+++ b/Lesson_27/UefiLessonsPkg/SmbiosInfo/SmbiosInfo.c
@@ -0,0 +1,88 @@
+#include <Library/UefiBootServicesTableLib.h>
+#include <Library/UefiLib.h>
+
+#include <Library/BaseMemoryLib.h>
+#include <Protocol/Smbios.h>
+
+CHAR8* GetRecordString(EFI_SMBIOS_TABLE_HEADER* Record, UINTN number)
+{
+  if (!number)
+    return "";
+
+  CHAR8* String = (CHAR8*)Record + Record->Length;
+  UINTN i=1;
+  while (i < number) {
+    String = String + AsciiStrSize(String);
+    i++;
+  }
+  return String;
+}
+
+EFI_STATUS
+EFIAPI
+UefiMain (
+  IN EFI_HANDLE        ImageHandle,
+  IN EFI_SYSTEM_TABLE  *SystemTable
+  )
+{
+  for (UINTN i=0; i<SystemTable->NumberOfTableEntries; i++) {
+    if (CompareGuid(&(SystemTable->ConfigurationTable[i].VendorGuid), &gEfiSmbiosTableGuid)) {
+      Print(L"SMBIOS table is placed at %p\n\n", SystemTable->ConfigurationTable[i].VendorTable);
+    }
+  } 
+
+  EFI_SMBIOS_PROTOCOL* SmbiosProtocol;
+  EFI_STATUS Status = gBS->LocateProtocol (
+                  &gEfiSmbiosProtocolGuid,
+                  NULL,
+                  (VOID**)&SmbiosProtocol
+                  );
+  if (EFI_ERROR (Status)) {
+    return Status;
+  }
+
+  EFI_SMBIOS_HANDLE SmbiosHandle = SMBIOS_HANDLE_PI_RESERVED;
+  EFI_SMBIOS_TABLE_HEADER* Record;
+  Status = SmbiosProtocol->GetNext(SmbiosProtocol,
+                                   &SmbiosHandle,
+                                   NULL,
+                                   &Record,
+                                   NULL);
+  while (!EFI_ERROR(Status)) {
+    Print (L"SMBIOS Type %d \n", Record->Type);
+    switch (Record->Type) {
+      case EFI_SMBIOS_TYPE_BIOS_INFORMATION: {
+        SMBIOS_TABLE_TYPE0* Type0Record = (SMBIOS_TABLE_TYPE0*) Record;
+        Print(L"\tVendor=%a\n", GetRecordString(Record, Type0Record->Vendor));
+        Print(L"\tBiosVersion=%a\n", GetRecordString(Record, Type0Record->BiosVersion));
+        Print(L"\tBiosReleaseDate=%a\n", GetRecordString(Record, Type0Record->BiosReleaseDate));
+        Print(L"\tBiosSegment=0x%x\n", Type0Record->BiosSegment);
+        Print(L"\tSystemBiosMajorRelease=0x%x\n", Type0Record->SystemBiosMajorRelease);
+        Print(L"\tSystemBiosMinorRelease=0x%x\n", Type0Record->SystemBiosMinorRelease);
+        break;
+      }
+      case EFI_SMBIOS_TYPE_SYSTEM_INFORMATION: {
+        SMBIOS_TABLE_TYPE1* Type1Record = (SMBIOS_TABLE_TYPE1*) Record;
+        Print(L"\tManufacturer=%a\n", GetRecordString(Record, Type1Record->Manufacturer));
+        Print(L"\tProductName=%a\n", GetRecordString(Record, Type1Record->ProductName));
+        Print(L"\tVersion=%a\n", GetRecordString(Record, Type1Record->Version));
+        Print(L"\tSerialNumber=%a\n", GetRecordString(Record, Type1Record->SerialNumber));
+        Print(L"\tUUID=%g\n", Type1Record->Uuid);
+        Print(L"\tWakeUpType=%d\n", Type1Record->WakeUpType);
+        Print(L"\tSKUNumber=%a\n", GetRecordString(Record, Type1Record->SKUNumber));
+        Print(L"\tFamily=%a\n", GetRecordString(Record, Type1Record->Family));
+        break;
+      }
+      default:
+        Print(L"\tTODO: Parsing for this table is not ready yet\n");
+        break;
+    }
+    Status = SmbiosProtocol->GetNext(SmbiosProtocol,
+                                     &SmbiosHandle,
+                                     NULL,
+                                     &Record,
+                                     NULL);
+  }
+  
+  return EFI_SUCCESS;
+}
diff --git a/Lesson_27/UefiLessonsPkg/SmbiosInfo/SmbiosInfo.inf b/Lesson_27/UefiLessonsPkg/SmbiosInfo/SmbiosInfo.inf
new file mode 100644
index 0000000..ab6013a
--- /dev/null
+++ b/Lesson_27/UefiLessonsPkg/SmbiosInfo/SmbiosInfo.inf
@@ -0,0 +1,24 @@
+[Defines]
+  INF_VERSION                    = 1.25
+  BASE_NAME                      = SmbiosInfo
+  FILE_GUID                      = 4a8836db-9e1d-4b7d-a785-f552340fba59
+  MODULE_TYPE                    = UEFI_APPLICATION
+  VERSION_STRING                 = 1.0
+  ENTRY_POINT                    = UefiMain
+
+[Sources]
+  SmbiosInfo.c
+
+[Packages]
+  MdePkg/MdePkg.dec
+
+[LibraryClasses]
+  UefiApplicationEntryPoint
+  UefiLib
+
+[Guids]
+  gEfiSmbiosTableGuid
+
+[Protocols]
+  gEfiSmbiosProtocolGuid
+
diff --git a/README.md b/README.md
index 93047ce..7e58b38 100644
--- a/README.md
+++ b/README.md
@@ -29,6 +29,7 @@ Lessons description:
 - Lesson 24: Dynamic/DynamicEx PCDs
 - Lesson 25: More on PCDs
 - Lesson 26: Tables referenced in `EFI_CONFIGURATION_TABLE`
+- Lesson 27: Get SMBIOS information with `dmem`/`EFI_SMBIOS_PROTOCOL`/`smbiosview`
 
 ______