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Re: [Qemu-devel] [PATCH v2 3/6] Support Physical Presence Interface Spec
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From: |
Igor Mammedov |
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Subject: |
Re: [Qemu-devel] [PATCH v2 3/6] Support Physical Presence Interface Spec |
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Date: |
Fri, 15 May 2015 17:13:32 +0200 |
On Fri, 8 May 2015 12:15:17 -0400
Stefan Berger <address@hidden> wrote:
> For automated management of a TPM device, implement the TCG Physical Presence
> Interface Specification that allows a root user on Linux (for example) to set
> an opcode for a sequence of TPM operations that the BIOS is supposed to
> execute
> upon reboot of the physical or virtual machine. A sequence of operations may
> for
> example involve giving up ownership of the TPM and activating and enabling the
> device.
>
> The sequences of operations are defined in table 2 in the specs to be found
> at the following link:
>
> http://www.trustedcomputinggroup.org/resources/tcg_physical_presence_interface_specification
>
> As an example, in recent versions of Linux the opcode (5) can be set as
> follows:
>
> cd /sys/devices/pnp0/00\:04/ppi
>
> echo 5 > request
>
> This ACPI implementation assumes that the underlying firmware (SeaBIOS)
> has 'thrown an anchor' into the f-segment. The anchor is identified by
> two signatures (TCG_MAGIC) surrounding a 64bit pointer. The structure
> in the f-segment is write-protected and holds a pointer to a structure
> in high memmory area where the ACPI code writes the opcode into and
> where it can read the last response from the BIOS.
>
> The supported opcodes are 1-11, 14, and 21-22. (see table 2 in spec)
> Also '0' is supported to 'clear' an intention.
>
>
> Signed-off-by: Stefan Berger <address@hidden>
> Cc: Michael Tsirkin <address@hidden>
> Cc: Kevin O'Connor <address@hidden>
> ---
> hw/i386/ssdt-tpm.dsl | 189
> ++++++++++++++++++++++++++++++++++++++++++++++++++
> include/hw/acpi/tpm.h | 20 ++++++
> 2 files changed, 209 insertions(+)
>
Ditto, please redo below ASL using C AML API.
API might not have all ASL ops you've used here but you can
reuse some from following series
"Generate ACPI v5.1 tables and expose them to guest over fw_cfg on ARM"
and add missing ones.
> diff --git a/hw/i386/ssdt-tpm.dsl b/hw/i386/ssdt-tpm.dsl
> index 75d9691..7d28899 100644
> --- a/hw/i386/ssdt-tpm.dsl
> +++ b/hw/i386/ssdt-tpm.dsl
> @@ -38,6 +38,195 @@ DefinitionBlock (
> Method (_STA, 0, NotSerialized) {
> Return (0x0F)
> }
> +
> + OperationRegion (TTIS, SystemMemory,
> + TPM_TIS_ADDR_BASE, TPM_TIS_ADDR_SIZE)
> +
> + // Define TPM Debug register
> + Field(TTIS, AnyAcc, NoLock, Preserve) {
> + Offset (0xf90),
> + TDBG, 32 // QEMU TIS Debug
I don't see it being used here,
What do you need it for?
> + }
> +
> + // Last accepted opcode
> + NAME(OP, Zero)
> +
> + // The base address in TIS 'RAM' where we exchange
> + // data with the BIOS
> + Name(ADDR, 0xfed40fa0)
> +
> + // Write given opcode into 'RAM'
> + Method (WRAM, 1, NotSerialized) {
> + // Write to high memory pointed to by ADDR
> + OperationRegion (HIGH, SystemMemory, ADDR,
> TPM_PPI_STRUCT_SIZE)
dynamic OperationRegion-s are better to be avoided, Windows can't/doesn't check
its correctness at table load time.
Put it at device scope so that guest OS would notice address collisions
if there would be any.
> + Field(HIGH, AnyAcc, NoLock, Preserve) {
> + SIG1, 32,
> + SIZE, 16,
> + CODE, 8
> + }
> + If (LAnd(
> + LEqual(SIG1, TCG_MAGIC),
> + LGreaterEqual(SIZE, 1))
> + ) {
> + // Write opcode for BIOS to find
> + Store(Arg0, CODE)
> + // Remember last opcode in CODE
> + Store(Arg0, OP)
> + Return ( 0 )
> + }
> + Return ( 1 )
> + }
> +
> + // read data from 'RAM'
> + Method (RRAM, 0, NotSerialized) {
> + Name (OPRE, Package(3) { 1, 0, 0})
> + // Read from memory pointed to by ADDR
> + OperationRegion (HIGH, SystemMemory, ADDR,
> TPM_PPI_STRUCT_SIZE)
with OperationRegion at device scope you can drop this.
> + Field(HIGH, AnyAcc, NoLock, Preserve) {
> + SIG1, 32,
> + SIZE, 16,
> + CODE, 8,
> + SUCC, 8,
> + CODO, 8,
> + RESP, 32
> + }
> + // Check signature and sufficient space
> + If (LAnd(
> + LEqual(SIG1, TCG_MAGIC),
using SIG1 seems to be redundant now, the same goes for BIOS part.
Why just not drop it?
> + LGreaterEqual(SIZE, 7)
> + )) {
> + Store(SUCC, Index(OPRE, 0))
> + Store(CODO, Index(OPRE, 1))
> + Store(RESP, Index(OPRE, 2))
> + }
> + return (OPRE)
> + }
> +
> + Method (_DSM, 4, NotSerialized) {
> + If (LEqual (Arg0,
> ToUUID("3DDDFAA6-361B-4EB4-A424-8D10089D1653"))) {
> +
> + // only supporting API revision 1
> + If (LNotEqual (Arg1, 1)) {
> + Return (Buffer (1) {0})
> + }
> +
> + Store(ToInteger(Arg2), Local0)
> + // standard DSM query function
> + If (LEqual (Local0, 0)) {
> + Return (Buffer () {0xFF, 0x01})
> + }
> +
> + // interface version
> + If (LEqual (Local0, 1)) {
> + Return ("1.2")
> + }
> +
> + // submit TPM operation
> + If (LEqual (Local0, 2)) {
> + // get opcode from package
> + Store(DerefOf(Index(Arg3, 0)), Local0)
> + // check for supported opcode
> + // supported opcodes: 0, 1-11, 14, 21-22
> + If (LOr(
> + LOr(
> + LAnd(
> + LGreaterEqual(Local0, 0),
> + LLessEqual(Local0, 11)
> + ),
> + LEqual(Local0, 14)
> + ),
> + LAnd(
> + LGreaterEqual(Local0, 21),
> + LLessEqual(Local0, 22)
> + )
> + ))
> + {
> + // Write the OP into TPM NVRAM
> + Store(WRAM ( Local0 ), Local1)
> + return (Local1)
> + } else {
> + Return (1)
> + }
> + }
> +
> + // get pending TPM operation
> + If (LEqual (Local0, 3)) {
> + NAME(PEOP, Package(2) { 0, 0 })
> +
> + Store ( 0 , Index(PEOP, 0))
> + Store ( OP, Index(PEOP, 1))
> +
> + Return (PEOP)
> + }
> +
> + // action to transition to pre-OS env.
> + If (LEqual (Local0, 4)) {
> + return (2) // Requiring reboot
> + }
> +
> + // get pre-OS TPM operation response
> + If (LEqual (Local0, 5)) {
> + Store (RRAM(), Local0)
> + return ( Local0 )
> + }
> +
> + // preferred user language
> + If (LEqual (Local0, 6)) {
> + return (3) // Not implemented
> + }
> +
> + // submit TPM operation v2
> + If (LEqual (Local0, 7)) {
> + Store(DerefOf(Index(Arg3, 0)), Local0)
> + // supported opcodes: 0, 1-11, 14, 21-22
check looks like the same as above, split out into a separate function?
> + If (LOr(
> + LOr(
> + LAnd(
> + LGreaterEqual(Local0, 0),
> + LLessEqual(Local0, 11)
> + ),
> + LEqual(Local0, 14)
> + ),
> + LAnd(
> + LGreaterEqual(Local0, 21),
> + LLessEqual(Local0, 22)
> + )
> + ))
> + {
> + // Write the OP into TPM NVRAM
> + Store(WRAM ( Local0 ), Local1)
> + return (Local1)
> + } else {
> + Return (1)
> + }
> + }
> +
> + // get user confirmation status
> + If (LEqual (Local0, 8)) {
> + Store(DerefOf(Index(Arg3,0)), Local0)
> + // supported opcodes: 0, 1-11, 14, 21-22
ditto
> + If (LOr(
> + LOr(
> + LAnd(
> + LGreaterEqual(Local0, 0),
> + LLessEqual(Local0, 11)
> + ),
> + LEqual(Local0, 14)
> + ),
> + LAnd(
> + LGreaterEqual(Local0, 21),
> + LLessEqual(Local0, 22)
> + )
> + ))
> + {
> + Return (4) // allowed, no user required
> + } else {
> + Return (0) // not implemented
> + }
> + }
> + }
> + return (Buffer() { 0x0 })
> + }
> }
> }
> }
> diff --git a/include/hw/acpi/tpm.h b/include/hw/acpi/tpm.h
> index 6d516c6..8d9c8dc 100644
> --- a/include/hw/acpi/tpm.h
> +++ b/include/hw/acpi/tpm.h
> @@ -31,4 +31,24 @@
>
> #define TPM2_START_METHOD_MMIO 6
>
> +/*
> + * Physical Presence Interface -- shared with the BIOS
> + */
> +#define TCG_MAGIC 0x41504354
> +
> +#if 0
> +struct tpm_ppi {
> + uint32_t sign1; // TCG_MAGIC
> + uint16_t size; // number of subsequent bytes for ACPI to access
> + uint8_t opcode; // set by ACPI
> + uint8_t failure; // set by BIOS (0 = success)
> + uint8_t recent_opcode; // set by BIOS
> + uint32_t response; // set by BIOS
> + uint8_t next_step; // BIOS only
> + uint32_t sign2; // TCG_MAGIC
> +} QEMU_PACKED;
> +#endif
> +
> +#define TPM_PPI_STRUCT_SIZE 18
> +
> #endif /* HW_ACPI_TPM_H */
- [Qemu-devel] [PATCH v2 0/6] Extend TPM support with a QEMU-external TPM, Stefan Berger, 2015/05/08
- [Qemu-devel] [PATCH v2 4/6] Introduce condition to notifiy waiters of completed command, Stefan Berger, 2015/05/08
- [Qemu-devel] [PATCH v2 2/6] Introduce RAM location in vendor specific area in TIS, Stefan Berger, 2015/05/08
- [Qemu-devel] [PATCH v2 5/6] Introduce condition in TPM backend for notification, Stefan Berger, 2015/05/08
- [Qemu-devel] [PATCH v2 1/6] Provide support for the CUSE TPM, Stefan Berger, 2015/05/08
- [Qemu-devel] [PATCH v2 6/6] Add support for VM suspend/resume for TPM TIS, Stefan Berger, 2015/05/08
- [Qemu-devel] [PATCH v2 3/6] Support Physical Presence Interface Spec, Stefan Berger, 2015/05/08