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authorBrijesh Singh <brijesh.singh@amd.com>2018-08-15 16:11:25 -0500
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-09-26 08:39:43 +0200
commit52b7326483715cce64474aab0367e0428a59ae90 (patch)
tree2ccb8f517234157b85c43127b3c241ac104a0adf
parentd6c9bc66491803a802b84d9da091ef2261ba637b (diff)
crypto: ccp - add timeout support in the SEV command
commit 3702a0585e64d70d5bf73bf3e943b8d6005b72c1 upstream. Currently, the CCP driver assumes that the SEV command issued to the PSP will always return (i.e. it will never hang). But recently, firmware bugs have shown that a command can hang. Since of the SEV commands are used in probe routines, this can cause boot hangs and/or loss of virtualization capabilities. To protect against firmware bugs, add a timeout in the SEV command execution flow. If a command does not complete within the specified timeout then return -ETIMEOUT and stop the driver from executing any further commands since the state of the SEV firmware is unknown. Cc: Tom Lendacky <thomas.lendacky@amd.com> Cc: Gary Hook <Gary.Hook@amd.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: linux-kernel@vger.kernel.org Signed-off-by: Brijesh Singh <brijesh.singh@amd.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> [Brijesh: Backported to 4.18..4.19 - offset change in few hunks] Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--drivers/crypto/ccp/psp-dev.c46
1 files changed, 41 insertions, 5 deletions
diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index 051b8c6bae64..a9c85095bd56 100644
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -38,6 +38,17 @@ static DEFINE_MUTEX(sev_cmd_mutex);
static struct sev_misc_dev *misc_dev;
static struct psp_device *psp_master;
+static int psp_cmd_timeout = 100;
+module_param(psp_cmd_timeout, int, 0644);
+MODULE_PARM_DESC(psp_cmd_timeout, " default timeout value, in seconds, for PSP commands");
+
+static int psp_probe_timeout = 5;
+module_param(psp_probe_timeout, int, 0644);
+MODULE_PARM_DESC(psp_probe_timeout, " default timeout value, in seconds, during PSP device probe");
+
+static bool psp_dead;
+static int psp_timeout;
+
static struct psp_device *psp_alloc_struct(struct sp_device *sp)
{
struct device *dev = sp->dev;
@@ -82,10 +93,19 @@ done:
return IRQ_HANDLED;
}
-static void sev_wait_cmd_ioc(struct psp_device *psp, unsigned int *reg)
+static int sev_wait_cmd_ioc(struct psp_device *psp,
+ unsigned int *reg, unsigned int timeout)
{
- wait_event(psp->sev_int_queue, psp->sev_int_rcvd);
+ int ret;
+
+ ret = wait_event_timeout(psp->sev_int_queue,
+ psp->sev_int_rcvd, timeout * HZ);
+ if (!ret)
+ return -ETIMEDOUT;
+
*reg = ioread32(psp->io_regs + PSP_CMDRESP);
+
+ return 0;
}
static int sev_cmd_buffer_len(int cmd)
@@ -133,12 +153,15 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
if (!psp)
return -ENODEV;
+ if (psp_dead)
+ return -EBUSY;
+
/* Get the physical address of the command buffer */
phys_lsb = data ? lower_32_bits(__psp_pa(data)) : 0;
phys_msb = data ? upper_32_bits(__psp_pa(data)) : 0;
- dev_dbg(psp->dev, "sev command id %#x buffer 0x%08x%08x\n",
- cmd, phys_msb, phys_lsb);
+ dev_dbg(psp->dev, "sev command id %#x buffer 0x%08x%08x timeout %us\n",
+ cmd, phys_msb, phys_lsb, psp_timeout);
print_hex_dump_debug("(in): ", DUMP_PREFIX_OFFSET, 16, 2, data,
sev_cmd_buffer_len(cmd), false);
@@ -154,7 +177,18 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
iowrite32(reg, psp->io_regs + PSP_CMDRESP);
/* wait for command completion */
- sev_wait_cmd_ioc(psp, &reg);
+ ret = sev_wait_cmd_ioc(psp, &reg, psp_timeout);
+ if (ret) {
+ if (psp_ret)
+ *psp_ret = 0;
+
+ dev_err(psp->dev, "sev command %#x timed out, disabling PSP \n", cmd);
+ psp_dead = true;
+
+ return ret;
+ }
+
+ psp_timeout = psp_cmd_timeout;
if (psp_ret)
*psp_ret = reg & PSP_CMDRESP_ERR_MASK;
@@ -886,6 +920,8 @@ void psp_pci_init(void)
psp_master = sp->psp_data;
+ psp_timeout = psp_probe_timeout;
+
if (sev_get_api_version())
goto err;