[Qemu-devel] [PATCH v9 6/6] tpm: add ACPI memory clear interface

[Marc-André Lureau]

This allows to pass the last failing test from the Windows HLK TPM 2.0
TCG PPI 1.3 tests.

The interface is described in the "TCG Platform Reset Attack
Mitigation Specification", chapter 6 "ACPI _DSM Function". According
to Laszlo, it's not so easy to implement in OVMF, he suggested to do
it in qemu instead.

Signed-off-by: Marc-André Lureau <address@hidden>
---
 hw/tpm/tpm_ppi.h     |  2 ++
 hw/i386/acpi-build.c | 46 ++++++++++++++++++++++++++++++++++++++++++++
 hw/tpm/tpm_crb.c     |  1 +
 hw/tpm/tpm_ppi.c     | 23 ++++++++++++++++++++++
 hw/tpm/tpm_tis.c     |  1 +
 docs/specs/tpm.txt   |  2 ++
 hw/tpm/trace-events  |  3 +++
 7 files changed, 78 insertions(+)

diff --git a/hw/tpm/tpm_ppi.h b/hw/tpm/tpm_ppi.h
index f6458bf87e..3239751e9f 100644
--- a/hw/tpm/tpm_ppi.h
+++ b/hw/tpm/tpm_ppi.h
@@ -23,4 +23,6 @@ typedef struct TPMPPI {
 bool tpm_ppi_init(TPMPPI *tpmppi, struct MemoryRegion *m,
                   hwaddr addr, Object *obj, Error **errp);
 
+void tpm_ppi_reset(TPMPPI *tpmppi);
+
 #endif /* TPM_TPM_PPI_H */
diff --git a/hw/i386/acpi-build.c b/hw/i386/acpi-build.c
index c5e9a6e11d..271c7240dc 100644
--- a/hw/i386/acpi-build.c
+++ b/hw/i386/acpi-build.c
@@ -1824,6 +1824,13 @@ build_tpm_ppi(TPMIf *tpm, Aml *dev)
     pprq = aml_name("PPRQ");
     pprm = aml_name("PPRM");
 
+    aml_append(dev,
+               aml_operation_region("TPP3", AML_SYSTEM_MEMORY,
+                                    aml_int(TPM_PPI_ADDR_BASE + 0x200),
+                                    0x1));
+    field = aml_field("TPP3", AML_BYTE_ACC, AML_NOLOCK, AML_PRESERVE);
+    aml_append(field, aml_named_field("MOVV", 8));
+    aml_append(dev, field);
     /*
      * DerefOf in Windows is broken with SYSTEM_MEMORY.  Use a dynamic
      * operation region inside of a method for getting FUNC[op].
@@ -2166,7 +2173,46 @@ build_tpm_ppi(TPMIf *tpm, Aml *dev)
             aml_append(ifctx, aml_return(aml_buffer(1, zerobyte)));
         }
         aml_append(method, ifctx);
+
+        ifctx = aml_if(
+            aml_equal(uuid,
+                      aml_touuid("376054ED-CC13-4675-901C-4756D7F2D45D")));
+        {
+            /* standard DSM query function */
+            ifctx2 = aml_if(aml_equal(function, zero));
+            {
+                uint8_t byte_list[1] = { 0x03 };
+                aml_append(ifctx2, aml_return(aml_buffer(1, byte_list)));
+            }
+            aml_append(ifctx, ifctx2);
+
+            /*
+             * TCG Platform Reset Attack Mitigation Specification 1.0 Ch.6
+             *
+             * Arg 2 (Integer): Function Index = 1
+             * Arg 3 (Package): Arguments = Package: Type: Integer
+             *                  Operation Value of the Request
+             * Returns: Type: Integer
+             *          0: Success
+             *          1: General Failure
+             */
+            ifctx2 = aml_if(aml_equal(function, one));
+            {
+                aml_append(ifctx2,
+                           aml_store(aml_derefof(aml_index(arguments, zero)),
+                                     op));
+                {
+                    aml_append(ifctx2, aml_store(op, aml_name("MOVV")));
+
+                    /* 0: success */
+                    aml_append(ifctx2, aml_return(zero));
+                }
+            }
+            aml_append(ifctx, ifctx2);
+        }
+        aml_append(method, ifctx);
     }
+
     aml_append(dev, method);
 }
 
diff --git a/hw/tpm/tpm_crb.c b/hw/tpm/tpm_crb.c
index b243222fd6..48f6a716ad 100644
--- a/hw/tpm/tpm_crb.c
+++ b/hw/tpm/tpm_crb.c
@@ -233,6 +233,7 @@ static void tpm_crb_reset(void *dev)
 {
     CRBState *s = CRB(dev);
 
+    tpm_ppi_reset(&s->ppi);
     tpm_backend_reset(s->tpmbe);
 
     memset(s->regs, 0, sizeof(s->regs));
diff --git a/hw/tpm/tpm_ppi.c b/hw/tpm/tpm_ppi.c
index 8b46b9dd4b..dbfe342ca2 100644
--- a/hw/tpm/tpm_ppi.c
+++ b/hw/tpm/tpm_ppi.c
@@ -16,8 +16,30 @@
 #include "qapi/error.h"
 #include "cpu.h"
 #include "sysemu/memory_mapping.h"
+#include "sysemu/reset.h"
 #include "migration/vmstate.h"
 #include "tpm_ppi.h"
+#include "trace.h"
+
+void tpm_ppi_reset(TPMPPI *tpmppi)
+{
+    char *ptr = memory_region_get_ram_ptr(&tpmppi->ram);
+
+    if (ptr[0x200] & 0x1) {
+        GuestPhysBlockList guest_phys_blocks;
+        GuestPhysBlock *block;
+
+        guest_phys_blocks_init(&guest_phys_blocks);
+        guest_phys_blocks_append(&guest_phys_blocks);
+        QTAILQ_FOREACH(block, &guest_phys_blocks.head, next) {
+            trace_tpm_ppi_memset(block->host_addr,
+                             block->target_end - block->target_start);
+            memset(block->host_addr, 0,
+                   block->target_end - block->target_start);
+        }
+        guest_phys_blocks_free(&guest_phys_blocks);
+    }
+}
 
 bool tpm_ppi_init(TPMPPI *tpmppi, struct MemoryRegion *m,
                   hwaddr addr, Object *obj, Error **errp)
@@ -27,5 +49,6 @@ bool tpm_ppi_init(TPMPPI *tpmppi, struct MemoryRegion *m,
     vmstate_register_ram(&tpmppi->ram, DEVICE(obj));
 
     memory_region_add_subregion(m, addr, &tpmppi->ram);
+
     return true;
 }
diff --git a/hw/tpm/tpm_tis.c b/hw/tpm/tpm_tis.c
index 70432ffe8b..d9bfa956cc 100644
--- a/hw/tpm/tpm_tis.c
+++ b/hw/tpm/tpm_tis.c
@@ -868,6 +868,7 @@ static void tpm_tis_reset(DeviceState *dev)
     s->be_buffer_size = MIN(tpm_backend_get_buffer_size(s->be_driver),
                             TPM_TIS_BUFFER_MAX);
 
+    tpm_ppi_reset(&s->ppi);
     tpm_backend_reset(s->be_driver);
 
     s->active_locty = TPM_TIS_NO_LOCALITY;
diff --git a/docs/specs/tpm.txt b/docs/specs/tpm.txt
index f3b7615161..54a3e1e4c5 100644
--- a/docs/specs/tpm.txt
+++ b/docs/specs/tpm.txt
@@ -121,6 +121,8 @@ layout:
  +----------+--------+--------+-------------------------------------------+
  | next_step|   0x1  |  0x159 | Operation to execute after reboot by      |
  |          |        |        | firmware. Used by firmware.               |
+ +----------+--------+--------+-------------------------------------------+
+ | movv     |   0x1  |  0x200 | Memory overwrite variable                 |
  +----------+--------+--------+-------------------------------------------+
 
    The following values are supported for the 'func' field. They correspond
diff --git a/hw/tpm/trace-events b/hw/tpm/trace-events
index 25bee0cecf..920d32ad55 100644
--- a/hw/tpm/trace-events
+++ b/hw/tpm/trace-events
@@ -51,3 +51,6 @@ tpm_tis_mmio_write_init_abort(void) "Initiating abort"
 tpm_tis_mmio_write_lowering_irq(void) "Lowering IRQ"
 tpm_tis_mmio_write_data2send(uint32_t value, unsigned size) "Data to send to 
TPM: 0x%08x (size=%d)"
 tpm_tis_pre_save(uint8_t locty, uint32_t rw_offset) "locty: %d, rw_offset = %u"
+
+# hw/tpm/tpm_ppi.c
+tpm_ppi_memset(uint8_t *ptr, size_t size) "memset: %p %zu"
-- 
2.18.0.547.g1d89318c48