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Message-ID: <20170317203447.hrzex4lss5mazmrl@intel.com>
Date: Fri, 17 Mar 2017 22:34:47 +0200
From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To: Jerry Snitselaar <jsnitsel@...hat.com>
Cc: Jarkko Sakkinen <jarkko.sakkinen@....fi>,
tpmdd-devel@...ts.sourceforge.net,
linux-security-module@...r.kernel.org, gang.wei@...el.com,
Peter Huewe <peterhuewe@....de>,
Marcel Selhorst <tpmdd@...horst.net>,
Jason Gunthorpe <jgunthorpe@...idianresearch.com>,
open list <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v3] tpm_crb: request and relinquish locality 0
On Fri, Mar 17, 2017 at 10:00:41AM -0700, Jerry Snitselaar wrote:
>
> Jarkko Sakkinen @ 2017-03-16 11:55 GMT:
>
> > On Wed, Mar 15, 2017 at 08:27:54PM -0700, Jerry Snitselaar wrote:
> >>
> >> Jerry Snitselaar @ 2017-03-16 02:38 GMT:
> >>
> >> > Jarkko Sakkinen @ 2017-03-15 05:57 GMT:
> >> >
> >> >> From: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> >> >>
> >> >> This commit adds support for requesting and relinquishing locality 0 in
> >> >> tpm_crb for the course of command transmission.
> >> >>
> >> >> In order to achieve this, two new callbacks are added to struct
> >> >> tpm_class_ops:
> >> >>
> >> >> - request_locality
> >> >> - relinquish_locality
> >> >>
> >> >> These are called before sending and receiving data from the TPM. We
> >> >> update also tpm_tis_core to use these callbacks. A small modification to
> >> >> request_locality() is done so that it returns -EBUSY instead of locality
> >> >> number when check_locality() fails in order to return something
> >> >> meaningful to the user space.
> >> >>
> >> >> With CRB interface you first set either requestAccess or relinquish bit
> >> >> from TPM_LOC_CTRL_x register and then wait for locAssigned and
> >> >> tpmRegValidSts bits to be set in the TPM_LOC_STATE_x register.
> >> >>
> >> >> The reason why were are doing this is to make sure that the driver
> >> >> will work properly with Intel TXT that uses locality 2. There's no
> >> >> explicit guarantee that it would relinquish this locality. In more
> >> >> general sense this commit enables tpm_crb to be a well behaving
> >> >> citizen in a multi locality environment.
> >> >>
> >> >> Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
> >> >> ---
> >> >> v2:
> >> >> - TPM driver level calllbacks
> >> >> v3:
> >> >> - Call ops->relinquish_locality only if ops->request_locality has been
> >> >> successful.
> >> >> - Do not reserve locality in nested tpm_transmit calls.
> >> >> - Check for tpmRegValidSts to make sure that the value in TPM_LOC_STATE_x is
> >> >> stable.
> >> >> drivers/char/tpm/tpm-interface.c | 10 ++++++++++
> >> >> drivers/char/tpm/tpm.h | 3 ++-
> >> >> drivers/char/tpm/tpm2-space.c | 15 +++++++++------
> >> >> drivers/char/tpm/tpm_crb.c | 41 ++++++++++++++++++++++++++++++++++++++++
> >> >> drivers/char/tpm/tpm_tis_core.c | 12 ++++--------
> >> >> include/linux/tpm.h | 3 ++-
> >> >> 6 files changed, 68 insertions(+), 16 deletions(-)
> >> >>
> >> >> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
> >> >> index 95c6f98..4cd216f 100644
> >> >> --- a/drivers/char/tpm/tpm-interface.c
> >> >> +++ b/drivers/char/tpm/tpm-interface.c
> >> >> @@ -384,6 +384,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> >> >> ssize_t len = 0;
> >> >> u32 count, ordinal;
> >> >> unsigned long stop;
> >> >> + bool no_locality = !(flags & TPM_TRANSMIT_HAS_LOCALITY);
> >> >>
> >> >> if (!tpm_validate_command(chip, buf, bufsiz))
> >> >> return -EINVAL;
> >> >> @@ -407,6 +408,12 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> >> >> if (chip->dev.parent)
> >> >> pm_runtime_get_sync(chip->dev.parent);
> >> >>
> >> >> + if (no_locality && chip->ops->request_locality) {
> >> >> + rc = chip->ops->request_locality(chip, 0);
> >> >> + if (rc)
> >> >> + goto out_no_locality;
> >> >> + }
> >> >> +
> >> >> rc = tpm2_prepare_space(chip, space, ordinal, buf);
> >> >> if (rc)
> >> >> goto out;
> >> >> @@ -466,6 +473,9 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> >> >> rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
> >> >>
> >> >> out:
> >> >> + if (no_locality && chip->ops->relinquish_locality)
> >> >> + chip->ops->relinquish_locality(chip, 0, false);
> >> >> +out_no_locality:
> >> >> if (chip->dev.parent)
> >> >> pm_runtime_put_sync(chip->dev.parent);
> >> >>
> >> >> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
> >> >> index 5eacb3f..ba2c00d 100644
> >> >> --- a/drivers/char/tpm/tpm.h
> >> >> +++ b/drivers/char/tpm/tpm.h
> >> >> @@ -521,7 +521,8 @@ extern const struct file_operations tpmrm_fops;
> >> >> extern struct idr dev_nums_idr;
> >> >>
> >> >> enum tpm_transmit_flags {
> >> >> - TPM_TRANSMIT_UNLOCKED = BIT(0),
> >> >> + TPM_TRANSMIT_UNLOCKED = BIT(0),
> >> >> + TPM_TRANSMIT_HAS_LOCALITY = BIT(1),
> >> >> };
> >> >>
> >> >> ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
> >> >> diff --git a/drivers/char/tpm/tpm2-space.c b/drivers/char/tpm/tpm2-space.c
> >> >> index d36d81e..43d05ab 100644
> >> >> --- a/drivers/char/tpm/tpm2-space.c
> >> >> +++ b/drivers/char/tpm/tpm2-space.c
> >> >> @@ -19,6 +19,9 @@
> >> >> #include <asm/unaligned.h>
> >> >> #include "tpm.h"
> >> >>
> >> >> +#define TPM_TRANSMIT_NESTED \
> >> >> + (TPM_TRANSMIT_UNLOCKED | TPM_TRANSMIT_HAS_LOCALITY)
> >> >> +
> >> >> enum tpm2_handle_types {
> >> >> TPM2_HT_HMAC_SESSION = 0x02000000,
> >> >> TPM2_HT_POLICY_SESSION = 0x03000000,
> >> >> @@ -39,7 +42,7 @@ static void tpm2_flush_sessions(struct tpm_chip *chip, struct tpm_space *space)
> >> >> for (i = 0; i < ARRAY_SIZE(space->session_tbl); i++) {
> >> >> if (space->session_tbl[i])
> >> >> tpm2_flush_context_cmd(chip, space->session_tbl[i],
> >> >> - TPM_TRANSMIT_UNLOCKED);
> >> >> + TPM_TRANSMIT_NESTED);
> >> >> }
> >> >> }
> >> >>
> >> >> @@ -84,7 +87,7 @@ static int tpm2_load_context(struct tpm_chip *chip, u8 *buf,
> >> >> tpm_buf_append(&tbuf, &buf[*offset], body_size);
> >> >>
> >> >> rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 4,
> >> >> - TPM_TRANSMIT_UNLOCKED, NULL);
> >> >> + TPM_TRANSMIT_NESTED, NULL);
> >> >> if (rc < 0) {
> >> >> dev_warn(&chip->dev, "%s: failed with a system error %d\n",
> >> >> __func__, rc);
> >> >> @@ -132,7 +135,7 @@ static int tpm2_save_context(struct tpm_chip *chip, u32 handle, u8 *buf,
> >> >> tpm_buf_append_u32(&tbuf, handle);
> >> >>
> >> >> rc = tpm_transmit_cmd(chip, NULL, tbuf.data, PAGE_SIZE, 0,
> >> >> - TPM_TRANSMIT_UNLOCKED, NULL);
> >> >> + TPM_TRANSMIT_NESTED, NULL);
> >> >> if (rc < 0) {
> >> >> dev_warn(&chip->dev, "%s: failed with a system error %d\n",
> >> >> __func__, rc);
> >> >> @@ -169,7 +172,7 @@ static void tpm2_flush_space(struct tpm_chip *chip)
> >> >> for (i = 0; i < ARRAY_SIZE(space->context_tbl); i++)
> >> >> if (space->context_tbl[i] && ~space->context_tbl[i])
> >> >> tpm2_flush_context_cmd(chip, space->context_tbl[i],
> >> >> - TPM_TRANSMIT_UNLOCKED);
> >> >> + TPM_TRANSMIT_NESTED);
> >> >>
> >> >> tpm2_flush_sessions(chip, space);
> >> >> }
> >> >> @@ -376,7 +379,7 @@ static int tpm2_map_response_header(struct tpm_chip *chip, u32 cc, u8 *rsp,
> >> >>
> >> >> return 0;
> >> >> out_no_slots:
> >> >> - tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_UNLOCKED);
> >> >> + tpm2_flush_context_cmd(chip, phandle, TPM_TRANSMIT_NESTED);
> >> >> dev_warn(&chip->dev, "%s: out of slots for 0x%08X\n", __func__,
> >> >> phandle);
> >> >> return -ENOMEM;
> >> >> @@ -468,7 +471,7 @@ static int tpm2_save_space(struct tpm_chip *chip)
> >> >> return rc;
> >> >>
> >> >> tpm2_flush_context_cmd(chip, space->context_tbl[i],
> >> >> - TPM_TRANSMIT_UNLOCKED);
> >> >> + TPM_TRANSMIT_NESTED);
> >> >> space->context_tbl[i] = ~0;
> >> >> }
> >> >>
> >> >> diff --git a/drivers/char/tpm/tpm_crb.c b/drivers/char/tpm/tpm_crb.c
> >> >> index 1dfc37e..eb2fcf1 100644
> >> >> --- a/drivers/char/tpm/tpm_crb.c
> >> >> +++ b/drivers/char/tpm/tpm_crb.c
> >> >> @@ -34,6 +34,16 @@ enum crb_defaults {
> >> >> CRB_ACPI_START_INDEX = 1,
> >> >> };
> >> >>
> >> >> +enum crb_loc_ctrl {
> >> >> + CRB_LOC_CTRL_REQUEST_ACCESS = BIT(0),
> >> >> + CRB_LOC_CTRL_RELINQUISH = BIT(1),
> >> >> +};
> >> >> +
> >> >> +enum crb_loc_state {
> >> >> + CRB_LOC_STATE_LOC_ASSIGNED = BIT(1),
> >> >> + CRB_LOC_STATE_TPM_REG_VALID_STS = BIT(7),
> >> >> +};
> >> >> +
> >> >> enum crb_ctrl_req {
> >> >> CRB_CTRL_REQ_CMD_READY = BIT(0),
> >> >> CRB_CTRL_REQ_GO_IDLE = BIT(1),
> >> >> @@ -172,6 +182,35 @@ static int __maybe_unused crb_cmd_ready(struct device *dev,
> >> >> return 0;
> >> >> }
> >> >>
> >> >> +static int crb_request_locality(struct tpm_chip *chip, int loc)
> >> >> +{
> >> >> + struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> >> >> + u32 value = CRB_LOC_STATE_LOC_ASSIGNED |
> >> >> + CRB_LOC_STATE_TPM_REG_VALID_STS;
> >> >> +
> >> >> + if (!priv->regs_h)
> >> >> + return 0;
> >> >> +
> >> >> + iowrite32(CRB_LOC_CTRL_REQUEST_ACCESS, &priv->regs_h->loc_ctrl);
> >> >> + if (!crb_wait_for_reg_32(&priv->regs_h->loc_state, value, value,
> >> >> + TPM2_TIMEOUT_C)) {
> >> >> + dev_warn(&chip->dev, "TPM_LOC_STATE_x.requestAccess timed out\n");
> >> >> + return -ETIME;
> >> >> + }
> >> >> +
> >> >> + return 0;
> >> >> +}
> >> >> +
> >> >> +static void crb_relinquish_locality(struct tpm_chip *chip, int loc, bool force)
> >> >> +{
> >> >> + struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> >> >> +
> >> >> + if (!priv->regs_h)
> >> >> + return;
> >> >> +
> >> >> + iowrite32(CRB_LOC_CTRL_RELINQUISH, &priv->regs_h->loc_ctrl);
> >> >> +}
> >> >> +
> >> >> static u8 crb_status(struct tpm_chip *chip)
> >> >> {
> >> >> struct crb_priv *priv = dev_get_drvdata(&chip->dev);
> >> >> @@ -278,6 +317,8 @@ static const struct tpm_class_ops tpm_crb = {
> >> >> .send = crb_send,
> >> >> .cancel = crb_cancel,
> >> >> .req_canceled = crb_req_canceled,
> >> >> + .request_locality = crb_request_locality,
> >> >> + .relinquish_locality = crb_relinquish_locality,
> >> >> .req_complete_mask = CRB_DRV_STS_COMPLETE,
> >> >> .req_complete_val = CRB_DRV_STS_COMPLETE,
> >> >> };
> >> >> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
> >> >> index fc0e9a2..c3cbe24 100644
> >> >> --- a/drivers/char/tpm/tpm_tis_core.c
> >> >> +++ b/drivers/char/tpm/tpm_tis_core.c
> >> >> @@ -73,7 +73,7 @@ static int check_locality(struct tpm_chip *chip, int l)
> >> >> return -1;
> >> >> }
> >> >>
> >> >> -static void release_locality(struct tpm_chip *chip, int l, int force)
> >> >> +static void release_locality(struct tpm_chip *chip, int l, bool force)
> >> >> {
> >> >> struct tpm_tis_data *priv = dev_get_drvdata(&chip->dev);
> >> >> int rc;
> >> >> @@ -97,7 +97,7 @@ static int request_locality(struct tpm_chip *chip, int l)
> >> >> long rc;
> >> >>
> >> >> if (check_locality(chip, l) >= 0)
> >> >> - return l;
> >> >> + return -EBUSY;
> >> >>
> >> >> rc = tpm_tis_write8(priv, TPM_ACCESS(l), TPM_ACCESS_REQUEST_USE);
> >> >> if (rc < 0)
> >> >> @@ -252,7 +252,6 @@ static int tpm_tis_recv(struct tpm_chip *chip, u8 *buf, size_t count)
> >> >>
> >> >> out:
> >> >> tpm_tis_ready(chip);
> >> >> - release_locality(chip, priv->locality, 0);
> >> >> return size;
> >> >> }
> >> >>
> >> >> @@ -268,9 +267,6 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
> >> >> size_t count = 0;
> >> >> bool itpm = priv->flags & TPM_TIS_ITPM_WORKAROUND;
> >> >>
> >> >> - if (request_locality(chip, 0) < 0)
> >> >> - return -EBUSY;
> >> >> -
> >> >> status = tpm_tis_status(chip);
> >> >> if ((status & TPM_STS_COMMAND_READY) == 0) {
> >> >> tpm_tis_ready(chip);
> >> >> @@ -329,7 +325,6 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
> >> >>
> >> >> out_err:
> >> >> tpm_tis_ready(chip);
> >> >> - release_locality(chip, priv->locality, 0);
> >> >> return rc;
> >> >> }
> >> >>
> >> >> @@ -390,7 +385,6 @@ static int tpm_tis_send_main(struct tpm_chip *chip, u8 *buf, size_t len)
> >> >> return len;
> >> >> out_err:
> >> >> tpm_tis_ready(chip);
> >> >> - release_locality(chip, priv->locality, 0);
> >> >> return rc;
> >> >> }
> >> >>
> >> >> @@ -681,6 +675,8 @@ static const struct tpm_class_ops tpm_tis = {
> >> >> .send = tpm_tis_send,
> >> >> .cancel = tpm_tis_ready,
> >> >> .update_timeouts = tpm_tis_update_timeouts,
> >> >> + .request_locality = request_locality,
> >> >> + .relinquish_locality = release_locality,
> >> >> .req_complete_mask = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
> >> >> .req_complete_val = TPM_STS_DATA_AVAIL | TPM_STS_VALID,
> >> >> .req_canceled = tpm_tis_req_canceled,
> >> >> diff --git a/include/linux/tpm.h b/include/linux/tpm.h
> >> >> index da158f0..65e05f9 100644
> >> >> --- a/include/linux/tpm.h
> >> >> +++ b/include/linux/tpm.h
> >> >> @@ -48,7 +48,8 @@ struct tpm_class_ops {
> >> >> u8 (*status) (struct tpm_chip *chip);
> >> >> bool (*update_timeouts)(struct tpm_chip *chip,
> >> >> unsigned long *timeout_cap);
> >> >> -
> >> >> + int (*request_locality)(struct tpm_chip *chip, int loc);
> >> >> + void (*relinquish_locality)(struct tpm_chip *chip, int loc, bool force);
> >> >> };
> >> >>
> >> >> #if defined(CONFIG_TCG_TPM) || defined(CONFIG_TCG_TPM_MODULE)
> >> >
> >> > This is broken for me on tpm_tis at the moment. release_locality only
> >> > actually follows through with releasing if you've set force or there is
> >> > a pending request for the TPM from another locality. So first time
> >> > through it requests and gets the locality, does its work, goes
> >> > to release it and doesn't because there is no pending request. Then
> >> > next time through, request_locality calls check_locality and returns
> >> > -EBUSY causing it to bail out of tpm_transmit.
> >>
> >> Actually I should amend that, I'd been debugging a bit. With the
> >> patch itself, tpm_tis_core_init() calls tpm2_probe() which fails
> >> because tpm_transmit_cmd -> tpm_transmit -> request_locality returns
> >> -EBUSY. There is a request_locality() call right before the
> >> tpm2_probe(). I'd dropped that as part of my debugging which allowed
> >> it to get further along, but then run into the problem mentioned above.
> >
> > I see.
> >
> > The request_locality call in tpm_tis_core_init should works with this
> > change because it does only whether the return value is zero so that
> > can be safely ignored.
> >
>
> Yes, the request_locality call works there, I just wasn't sure it was
> necessary since tpm2_probe will end up calling it (and returning
> -EBUSY). I guess it would be needed prior to the probe_itpm call since
> nothing in there calls request_locality now. It seems a bit odd
> that probe_iptm calls release_locality twice though.
>
> > The send data case totally breaks.
> >
> > Changing the return value to -EBUSY was a stupid mistake from my side.
> >
> > I'll try revise this a bit in a way that the API will allow positive
> > value for stating that the given locality has been already taking.
> >
>
> Is there a big performance hit with requesting and releasing locality?
> If instead it just released it when release_locality is called I think
> the changes are pretty minor.
I wouldn't think so with modern TPMs. I could go with this.
/Jarkko
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