linux-kernel - [PATCH 3/3] tpm: vtpm_proxy: Avoid reading host log when using a virtual device

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Message-Id: <20210309031954.6232-4-stefanb@linux.ibm.com>
Date:   Mon,  8 Mar 2021 22:19:54 -0500
From:   Stefan Berger <stefanb@...ux.ibm.com>
To:     peterhuewe@....de, jarkko@...nel.org
Cc:     jgg@...pe.ca, linux-integrity@...r.kernel.org,
        linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org, Stefan Berger <stefanb@...ux.ibm.com>
Subject: [PATCH 3/3] tpm: vtpm_proxy: Avoid reading host log when using a virtual device

Avoid allocating memory and reading the host log when a virtual device
is used since this log is of no use to that driver. A virtual
device can be identified through the flag TPM_CHIP_FLAG_VIRTUAL, which
is only set for the tpm_vtpm_proxy driver.

Fixes: 6f99612e2500 ("tpm: Proxy driver for supporting multiple emulated TPMs")
Signed-off-by: Stefan Berger <stefanb@...ux.ibm.com>
---
 drivers/char/tpm/eventlog/common.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/char/tpm/eventlog/common.c b/drivers/char/tpm/eventlog/common.c
index 7460f230bae4..8512ec76d526 100644
--- a/drivers/char/tpm/eventlog/common.c
+++ b/drivers/char/tpm/eventlog/common.c
@@ -107,6 +107,9 @@ void tpm_bios_log_setup(struct tpm_chip *chip)
 	int log_version;
 	int rc = 0;
 
+	if (chip->flags & TPM_CHIP_FLAG_VIRTUAL)
+		return;
+
 	rc = tpm_read_log(chip);
 	if (rc < 0)
 		return;
-- 
2.29.2