Commit f426d2b2 authored by Tom Lendacky's avatar Tom Lendacky Committed by Herbert Xu
Browse files

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: 200664d5

 ("crypto: ccp: Add Secure Encrypted Virtualization (SEV) command support")
Cc: <stable@vger.kernel.org> # 4.16.x-
Signed-off-by: default avatarTom Lendacky <thomas.lendacky@amd.com>
Reviewed-by: default avatarBrijesh Singh <brijesh.singh@amd.com>
Acked-by: default avatarGary R Hook <gary.hook@amd.com>
Acked-by: default avatarGary R Hook <gary.hook@amd.com>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 5c324a2f
...@@ -84,8 +84,6 @@ static irqreturn_t psp_irq_handler(int irq, void *data) ...@@ -84,8 +84,6 @@ static irqreturn_t psp_irq_handler(int irq, void *data)
static void sev_wait_cmd_ioc(struct psp_device *psp, unsigned int *reg) 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); wait_event(psp->sev_int_queue, psp->sev_int_rcvd);
*reg = ioread32(psp->io_regs + PSP_CMDRESP); *reg = ioread32(psp->io_regs + PSP_CMDRESP);
} }
...@@ -148,6 +146,8 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) ...@@ -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_lsb, psp->io_regs + PSP_CMDBUFF_ADDR_LO);
iowrite32(phys_msb, psp->io_regs + PSP_CMDBUFF_ADDR_HI); iowrite32(phys_msb, psp->io_regs + PSP_CMDBUFF_ADDR_HI);
psp->sev_int_rcvd = 0;
reg = cmd; reg = cmd;
reg <<= PSP_CMDRESP_CMD_SHIFT; reg <<= PSP_CMDRESP_CMD_SHIFT;
reg |= PSP_CMDRESP_IOC; reg |= PSP_CMDRESP_IOC;
......
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