On 1/25/2024 5:29 PM, Borislav Petkov wrote:
> On Wed, Dec 20, 2023 at 08:43:45PM +0530, Nikunj A Dadhania wrote:
>> -int snp_issue_guest_request(u64 exit_code, struct snp_req_data *input, struct snp_guest_request_ioctl *rio)
>> +int snp_issue_guest_request(struct snp_guest_req *req, struct snp_req_data *input,
>> + struct snp_guest_request_ioctl *rio)
>> {
>> struct ghcb_state state;
>> struct es_em_ctxt ctxt;
>> unsigned long flags;
>> struct ghcb *ghcb;
>> + u64 exit_code;
>
> Silly local vars. Just use req->exit_code everywhere instead.
Sure, will change.
>
>> int ret;
>>
>> rio->exitinfo2 = SEV_RET_NO_FW_CALL;
>> + if (!req)
>> + return -EINVAL;
>
> Such tests are done under the variable which is assigned, not randomly.
>
> Also, what's the point in testing req? Will that ever be NULL? What are
> you actually protecting against here?
Right, and in the later code, this is checked at snp_send_guest_request() API. So this is redundant.
>> diff --git a/drivers/virt/coco/sev-guest/sev-guest.c b/drivers/virt/coco/sev-guest/sev-guest.c
>> index 469e10d9bf35..5cafbd1c42cb 100644
>> --- a/drivers/virt/coco/sev-guest/sev-guest.c
>> +++ b/drivers/virt/coco/sev-guest/sev-guest.c
>> @@ -27,8 +27,7 @@
>>
>> #include <asm/svm.h>
>> #include <asm/sev.h>
>> -
>> -#include "sev-guest.h"
>> +#include <asm/sev-guest.h>
>>
>> #define DEVICE_NAME "sev-guest"
>>
>> @@ -169,7 +168,7 @@ static struct aesgcm_ctx *snp_init_crypto(u8 *key, size_t keylen)
>> return ctx;
>> }
>>
>> -static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, void *payload, u32 sz)
>> +static int verify_and_dec_payload(struct snp_guest_dev *snp_dev, struct snp_guest_req *guest_req)
>
> So we call the request everywhere "req". But you've called it
> "guest_req" here because...
Yes, I was thinking about it and came up with this.
>
>> {
>> struct snp_guest_msg *resp = &snp_dev->secret_response;
>> struct snp_guest_msg *req = &snp_dev->secret_request;
>
> ... there already is a "req" variable which is not a guest request thing
> but a guest message. So why don't you call it "req_msg" instead and the
> "resp" "resp_msg" so that it is clear what is what?
>
This naming is much better, thanks.
> And then you can call the actual request var "req" and then the code
> becomes more readable...
>
> ...
>
>> static int get_report(struct snp_guest_dev *snp_dev, struct snp_guest_request_ioctl *arg)
>> {
>> struct snp_report_req *req = &snp_dev->req.report;
>> + struct snp_guest_req guest_req = {0};
>
> You have the same issue here.
>
> If we aim at calling the local vars in every function the same, the code
> becomes automatically much more readable.
>
> And so on...
Will change accordingly,
Regards
Nikunj
