[Qemu-devel] [RFC PATCH 3/3] acpi: Build TPM Physical Presence interface

[Stefan Berger <stefanb@linux.vnet.ibm.com>]

The TPM Physical Presence interface consists of an ACPI part, a shared
memory part, and code in the firmware. Users can send messages to the
firmware by writing a code into the shared memory through invoking the
ACPI code. When a reboot happens, the firmware looks for the code and
acts on it by sending sequences of commands to the TPM.

This patch adds the ACPI code. It is similar to the one in EDK2 but doesn't
assume that SMIs are necessary to use. Besides that it tests the code
entered by the user and checks whether it is supported. The range of codes
supported matches the range of codes supported in SeaBIOS. It uses the same
datastructure for the shared memory as EDK2 does so that EDK2 and SeaBIOS
could both make use of the shared memory.

The underlying TCG specification is accessible from the following page.

https://trustedcomputinggroup.org/tcg-physical-presence-interface-specification/

This patch implements version 1.20.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>
---
 hw/i386/acpi-build.c  | 227 ++++++++++++++++++++++++++++++++++++++++++++++++++
 include/hw/acpi/tpm.h |  15 ++++
 2 files changed, 242 insertions(+)

diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index 18b939e..e3905a3 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -42,6 +42,7 @@
 #include "hw/acpi/memory_hotplug.h"
 #include "sysemu/tpm.h"
 #include "hw/acpi/tpm.h"
+#include "hw/tpm/tpm_ppi.h"
 #include "hw/acpi/vmgenid.h"
 #include "sysemu/tpm_backend.h"
 #include "hw/timer/mc146818rtc_regs.h"
@@ -1860,6 +1861,231 @@ static Aml *build_q35_osc_method(void)
 }
 
 static void
+build_tpm_ppi(Aml *dev, TPMVersion tpm_version)
+{
+    Aml *method, *field, *ifctx, *ifctx2, *ifctx3, *pak;
+
+    aml_append(dev,
+               aml_operation_region("TPPI", AML_SYSTEM_MEMORY,
+                                    aml_int(TPM_PPI_ADDR_BASE),
+                                    TPM_PPI_STRUCT_SIZE));
+
+    field = aml_field("TPPI", AML_ANY_ACC, AML_NOLOCK, AML_PRESERVE);
+    aml_append(field, aml_named_field("PPIN",
+               sizeof(uint8_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("PPIP",
+               sizeof(uint32_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("PPRP",
+               sizeof(uint32_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("PPRQ",
+               sizeof(uint32_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("PPRM",
+               sizeof(uint32_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("LPPR",
+               sizeof(uint32_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("FRET",
+               sizeof(uint32_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("RES1",
+               sizeof(uint8_t) * BITS_PER_BYTE));
+    aml_append(field, aml_named_field("RES2",
+               sizeof(uint32_t) * BITS_PER_BYTE * 4));
+    aml_append(field, aml_named_field("FAIL",
+               sizeof(uint32_t) * BITS_PER_BYTE));
+    aml_append(dev, field);
+
+    /*
+     * Write the given operations code into 'PPRQ'.
+     */
+    method = aml_method("WRAM", 2, AML_SERIALIZED);
+    {
+        aml_append(method, aml_store(aml_arg(0), aml_name("PPRQ")));
+        aml_append(method, aml_store(aml_arg(1), aml_name("PPRM")));
+        /* 0 = Success */
+        aml_append(method, aml_return(aml_int(0)));
+    }
+    aml_append(dev, method);
+
+    /*
+     * CKOP: Check whether the opcode is valid
+     */
+    if (tpm_version == TPM_VERSION_1_2) {
+        method = aml_method("CKOP", 1, AML_NOTSERIALIZED);
+        {
+            ifctx = aml_if(
+                      aml_or(
+                        aml_or(
+                          aml_and(
+                            aml_lgreater_equal(aml_arg(0), aml_int(0)),
+                            aml_lless_equal(aml_arg(0), aml_int(11)),
+                            NULL
+                          ),
+                          aml_equal(aml_arg(0), aml_int(14)),
+                          NULL
+                        ),
+                        aml_and(
+                          aml_lgreater_equal(aml_arg(0), aml_int(21)),
+                          aml_lless_equal(aml_arg(0), aml_int(22)),
+                          NULL
+                       ),
+                       NULL
+                      )
+                    );
+            {
+                aml_append(ifctx, aml_return(aml_int(1)));
+            }
+            aml_append(method, ifctx);
+
+            aml_append(method, aml_return(aml_int(0)));
+        }
+    } else {
+        method = aml_method("CKOP", 1, AML_NOTSERIALIZED);
+        {
+            ifctx = aml_if(
+                      aml_equal(aml_arg(0), aml_int(0))
+                    );
+            {
+                aml_append(ifctx, aml_return(aml_int(1)));
+            }
+            aml_append(method, ifctx);
+
+            aml_append(method, aml_return(aml_int(0)));
+        }
+    }
+    aml_append(dev, method);
+
+    method = aml_method("_DSM", 4, AML_SERIALIZED);
+    {
+        uint8_t zerobyte[1] = { 0 };
+
+        ifctx = aml_if(
+                  aml_equal(aml_arg(0),
+                            aml_touuid("3DDDFAA6-361B-4EB4-A424-8D10089D1653"))
+                );
+        {
+            aml_append(ifctx,
+                       aml_store(aml_to_integer(aml_arg(2)), aml_local(0)));
+
+            /* standard DSM query function */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(0)));
+            {
+                uint8_t byte_list[2] = { 0xff, 0x01 };
+                aml_append(ifctx2, aml_return(aml_buffer(2, byte_list)));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* interface version: 1.2 */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(1)));
+            {
+                aml_append(ifctx2, aml_return(aml_string("1.2")));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* submit TPM operation */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(2)));
+            {
+                aml_append(ifctx2,
+                           aml_store(aml_derefof(aml_index(aml_arg(3),
+                                                           aml_int(0))),
+                                     aml_local(0)));
+                ifctx3 = aml_if(aml_call1("CKOP", aml_local(0)));
+                {
+                    aml_append(ifctx3,
+                               aml_return(aml_call2("WRAM",
+                                                    aml_local(0),
+                                                    aml_int(0))));
+                }
+                aml_append(ifctx2, ifctx3);
+                aml_append(ifctx2, aml_return(aml_int(1)));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* get pending TPM operation */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(3)));
+            {
+                pak = aml_package(2);
+                aml_append(pak, aml_int(0));
+                aml_append(pak, aml_name("PPRQ"));
+                aml_append(ifctx2, aml_return(pak));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* get platform-specific action to transition to pre-OS env. */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(4)));
+            {
+                /* 2 = reboot */
+                aml_append(ifctx2, aml_return(aml_int(2)));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* get TPM operation response */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(5)));
+            {
+                pak = aml_package(3);
+
+                aml_append(pak, aml_name("FAIL"));
+                aml_append(pak, aml_name("LPPR"));
+                aml_append(pak, aml_name("PPRP"));
+
+                aml_append(ifctx2, aml_return(pak));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* submit preferred user language */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(6)));
+            {
+                /* 3 = not implemented */
+                aml_append(ifctx2, aml_return(aml_int(3)));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* submit TPM operation v2 */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(7)));
+            {
+                aml_append(ifctx2,
+                           aml_store(aml_derefof(aml_index(aml_arg(3),
+                                                           aml_int(0))),
+                                     aml_local(0)));
+                ifctx3 = aml_if(aml_call1("CKOP", aml_local(0)));
+                {
+                    aml_append(ifctx3,
+                               aml_store(aml_call2("WRAM",
+                                                   aml_local(0),
+                                                   aml_int(0)),
+                                         aml_local(1)));
+                    aml_append(ifctx3, aml_return(aml_local(1)));
+                }
+                aml_append(ifctx2, ifctx3);
+                /* 1 = requested operation not implemented */
+                aml_append(ifctx2, aml_return(aml_int(1)));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /* get user confirmation status for operation */
+            ifctx2 = aml_if(aml_equal(aml_local(0), aml_int(8)));
+            {
+                aml_append(ifctx2,
+                           aml_store(aml_derefof(aml_index(aml_arg(3),
+                                                           aml_int(0))),
+                                     aml_local(0)));
+                ifctx3 = aml_if(aml_call1("CKOP", aml_local(0)));
+                {
+                    /* 4 = Allowed and physically present user not required */
+                    aml_append(ifctx3, aml_return(aml_int(4)));
+                }
+                aml_append(ifctx2, ifctx3);
+                /* 0 = requested operation not implemented */
+                aml_append(ifctx2, aml_return(aml_int(0)));
+            }
+            aml_append(ifctx, ifctx2);
+
+            aml_append(ifctx, aml_return(aml_buffer(1, zerobyte)));
+        }
+        aml_append(method, ifctx);
+    }
+    aml_append(dev, method);
+}
+
+static void
 build_dsdt(GArray *table_data, BIOSLinker *linker,
            AcpiPmInfo *pm, AcpiMiscInfo *misc,
            Range *pci_hole, Range *pci_hole64, MachineState *machine)
@@ -2218,6 +2444,7 @@ build_dsdt(GArray *table_data, BIOSLinker *linker,
                  */
                 /* aml_append(crs, aml_irq_no_flags(TPM_TIS_IRQ)); */
                 aml_append(dev, aml_name_decl("_CRS", crs));
+                build_tpm_ppi(dev, misc->tpm_version);
                 aml_append(scope, dev);
             }
 
diff --git a/include/hw/acpi/tpm.h b/include/hw/acpi/tpm.h
index d9b7452..23f5da1 100644
--- a/include/hw/acpi/tpm.h
+++ b/include/hw/acpi/tpm.h
@@ -37,4 +37,19 @@
 #define TPM_PPI_ADDR_SIZE           0x100
 #define TPM_PPI_ADDR_BASE           0xffff0000
 
+struct tpm_ppi {
+    uint8_t ppin;            /* set by BIOS; currently initialization flag */
+    uint32_t ppip;           /* set by ACPI; not used */
+    uint32_t pprp;           /* response from TPM; set by BIOS */
+    uint32_t pprq;           /* opcode; set by ACPI */
+    uint32_t pprm;           /* parameter for opcode; set by ACPI */
+    uint32_t lppr;           /* last opcode; set by BIOS */
+    uint32_t fret;           /* set by ACPI; not used*/
+    uint32_t res1;           /* reserved */
+    uint32_t res2[4];        /* reserved */
+    uint32_t fail;           /* set by BIOS (0 = success) */
+} QEMU_PACKED;
+
+#define TPM_PPI_STRUCT_SIZE  sizeof(struct tpm_ppi)
+
 #endif /* HW_ACPI_TPM_H */
-- 
2.5.5