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crypto: ccp - Fix command completion detection race 

The wait_event() function is used to detect command completion.  The
interrupt handler will set the wait condition variable when the interrupt
is triggered.  However, the variable used for wait_event() is initialized
after the command has been submitted, which can create a race condition
with the interrupt handler and result in the wait_event() never returning.
Move the initialization of the wait condition variable to just before
command submission.

Fixes: 200664d523 ("crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support")
Cc: <stable@vger.kernel.org> # 4.16.x-
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Acked-by: Gary R Hook <gary.hook@amd.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
This commit is contained in:
Tom Lendacky 2018-07-03 12:11:33 -05:00 committed by Herbert Xu
parent 5c324a2ffa
commit f426d2b20f
1 changed files with 2 additions and 2 deletions
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4
drivers/crypto/ccp/psp-dev.c
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@ -84,8 +84,6 @@ done:
static void sev_wait_cmd_ioc(struct psp_device *psp, unsigned int *reg)
{
psp->sev_int_rcvd = 0;
wait_event(psp->sev_int_queue, psp->sev_int_rcvd);
*reg = ioread32(psp->io_regs + PSP_CMDRESP);
}
@ -148,6 +146,8 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret)
iowrite32(phys_lsb, psp->io_regs + PSP_CMDBUFF_ADDR_LO);
iowrite32(phys_msb, psp->io_regs + PSP_CMDBUFF_ADDR_HI);
psp->sev_int_rcvd = 0;
reg = cmd;
reg <<= PSP_CMDRESP_CMD_SHIFT;
reg |= PSP_CMDRESP_IOC;