116 lines
3.7 KiB
Diff
116 lines
3.7 KiB
Diff
From: Brijesh Singh <brijesh.singh@amd.com>
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Date: Wed, 15 Aug 2018 16:11:25 -0500
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Subject: crypto: ccp - add timeout support in the SEV command
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Origin: https://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6.git/commit?id=3702a0585e64d70d5bf73bf3e943b8d6005b72c1
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Currently, the CCP driver assumes that the SEV command issued to the PSP
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will always return (i.e. it will never hang). But recently, firmware bugs
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have shown that a command can hang. Since of the SEV commands are used
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in probe routines, this can cause boot hangs and/or loss of virtualization
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capabilities.
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To protect against firmware bugs, add a timeout in the SEV command
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execution flow. If a command does not complete within the specified
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timeout then return -ETIMEOUT and stop the driver from executing any
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further commands since the state of the SEV firmware is unknown.
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Cc: Tom Lendacky <thomas.lendacky@amd.com>
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Cc: Gary Hook <Gary.Hook@amd.com>
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Cc: Herbert Xu <herbert@gondor.apana.org.au>
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Cc: linux-kernel@vger.kernel.org
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Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
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Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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---
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drivers/crypto/ccp/psp-dev.c | 46 ++++++++++++++++++++++++++++++++----
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1 file changed, 41 insertions(+), 5 deletions(-)
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--- a/drivers/crypto/ccp/psp-dev.c
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+++ b/drivers/crypto/ccp/psp-dev.c
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@@ -38,6 +38,17 @@ static DEFINE_MUTEX(sev_cmd_mutex);
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static struct sev_misc_dev *misc_dev;
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static struct psp_device *psp_master;
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+static int psp_cmd_timeout = 100;
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+module_param(psp_cmd_timeout, int, 0644);
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+MODULE_PARM_DESC(psp_cmd_timeout, " default timeout value, in seconds, for PSP commands");
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+
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+static int psp_probe_timeout = 5;
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+module_param(psp_probe_timeout, int, 0644);
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+MODULE_PARM_DESC(psp_probe_timeout, " default timeout value, in seconds, during PSP device probe");
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+
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+static bool psp_dead;
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+static int psp_timeout;
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+
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static struct psp_device *psp_alloc_struct(struct sp_device *sp)
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{
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struct device *dev = sp->dev;
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@@ -82,10 +93,19 @@ done:
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return IRQ_HANDLED;
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}
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-static void sev_wait_cmd_ioc(struct psp_device *psp, unsigned int *reg)
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+static int sev_wait_cmd_ioc(struct psp_device *psp,
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+ unsigned int *reg, unsigned int timeout)
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{
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- wait_event(psp->sev_int_queue, psp->sev_int_rcvd);
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+ int ret;
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+
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+ ret = wait_event_timeout(psp->sev_int_queue,
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+ psp->sev_int_rcvd, timeout * HZ);
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+ if (!ret)
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+ return -ETIMEDOUT;
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+
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*reg = ioread32(psp->io_regs + psp->vdata->cmdresp_reg);
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+
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+ return 0;
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}
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static int sev_cmd_buffer_len(int cmd)
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@@ -133,12 +153,15 @@ static int __sev_do_cmd_locked(int cmd,
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if (!psp)
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return -ENODEV;
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+ if (psp_dead)
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+ return -EBUSY;
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+
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/* Get the physical address of the command buffer */
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phys_lsb = data ? lower_32_bits(__psp_pa(data)) : 0;
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phys_msb = data ? upper_32_bits(__psp_pa(data)) : 0;
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- dev_dbg(psp->dev, "sev command id %#x buffer 0x%08x%08x\n",
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- cmd, phys_msb, phys_lsb);
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+ dev_dbg(psp->dev, "sev command id %#x buffer 0x%08x%08x timeout %us\n",
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+ cmd, phys_msb, phys_lsb, psp_timeout);
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print_hex_dump_debug("(in): ", DUMP_PREFIX_OFFSET, 16, 2, data,
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sev_cmd_buffer_len(cmd), false);
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@@ -154,7 +177,18 @@ static int __sev_do_cmd_locked(int cmd,
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iowrite32(reg, psp->io_regs + psp->vdata->cmdresp_reg);
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/* wait for command completion */
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- sev_wait_cmd_ioc(psp, ®);
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+ ret = sev_wait_cmd_ioc(psp, ®, psp_timeout);
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+ if (ret) {
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+ if (psp_ret)
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+ *psp_ret = 0;
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+
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+ dev_err(psp->dev, "sev command %#x timed out, disabling PSP \n", cmd);
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+ psp_dead = true;
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+
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+ return ret;
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+ }
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+
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+ psp_timeout = psp_cmd_timeout;
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if (psp_ret)
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*psp_ret = reg & PSP_CMDRESP_ERR_MASK;
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@@ -888,6 +922,8 @@ void psp_pci_init(void)
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psp_master = sp->psp_data;
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+ psp_timeout = psp_probe_timeout;
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+
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if (sev_get_api_version())
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goto err;
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