On 4/5/21 11:33 AM, Sean Christopherson wrote: > On Mon, Apr 05, 2021, Tom Lendacky wrote: >> On 4/2/21 6:36 PM, Sean Christopherson wrote: >>> diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c >>> index 6556d220713b..4c513318f16a 100644 >>> --- a/drivers/crypto/ccp/sev-dev.c >>> +++ b/drivers/crypto/ccp/sev-dev.c >>> @@ -141,6 +141,7 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) >>> struct sev_device *sev; >>> unsigned int phys_lsb, phys_msb; >>> unsigned int reg, ret = 0; >>> + int buf_len; >>> >>> if (!psp || !psp->sev_data) >>> return -ENODEV; >>> @@ -150,7 +151,11 @@ static int __sev_do_cmd_locked(int cmd, void *data, int *psp_ret) >>> >>> sev = psp->sev_data; >>> >>> - if (data && WARN_ON_ONCE(is_vmalloc_addr(data))) >>> + buf_len = sev_cmd_buffer_len(cmd); >>> + if (WARN_ON_ONCE(!!data != !!buf_len)) >> >> Seems a bit confusing to me. Can this just be: >> >> if (WARN_ON_ONCE(data && !buf_len)) > > Or as Christophe pointed out, "!data != !buf_len". > >> Or is this also trying to catch the case where buf_len is non-zero but >> data is NULL? > > Ya. It's not necessary to detect "buf_len && !data", but it doesn't incur > additional cost. Is there a reason _not_ to disallow that? Nope, no reason. I was just trying to process all the not signs :) Thanks, Tom >
