On 3/28/24 20:55, Peter Maydell wrote:
On Wed, 27 Mar 2024 at 05:41, Harsh Prateek Bora <hars...@linux.ibm.com> wrote:
On 3/26/24 21:32, Peter Maydell wrote:
On Tue, 12 Mar 2024 at 17:11, Nicholas Piggin <npig...@gmail.com> wrote:
From: Harsh Prateek Bora <hars...@linux.ibm.com>
Introduce the nested PAPR hcalls:
- H_GUEST_GET_STATE which is used to get state of a nested guest or
a guest VCPU. The value field for each element in the request is
destination to be updated to reflect current state on success.
- H_GUEST_SET_STATE which is used to modify the state of a guest or
a guest VCPU. On success, guest (or its VCPU) state shall be
updated as per the value field for the requested element(s).
Reviewed-by: Nicholas Piggin <npig...@gmail.com>
Signed-off-by: Michael Neuling <mi...@neuling.org>
Signed-off-by: Harsh Prateek Bora <hars...@linux.ibm.com>
Signed-off-by: Nicholas Piggin <npig...@gmail.com>
Hi; Coverity points out a problem with this code (CID 1540008, 1540009):
+static target_ulong h_guest_getset_state(PowerPCCPU *cpu,
+ SpaprMachineState *spapr,
+ target_ulong *args,
+ bool set)
+{
+ target_ulong flags = args[0];
+ target_ulong lpid = args[1];
+ target_ulong vcpuid = args[2];
+ target_ulong buf = args[3];
+ target_ulong buflen = args[4];
+ struct guest_state_request gsr;
+ SpaprMachineStateNestedGuest *guest;
+
+ guest = spapr_get_nested_guest(spapr, lpid);
+ if (!guest) {
+ return H_P2;
+ }
+ gsr.buf = buf;
+ assert(buflen <= GSB_MAX_BUF_SIZE);
+ gsr.len = buflen;
+ gsr.flags = 0;
+ if (flags & H_GUEST_GETSET_STATE_FLAG_GUEST_WIDE) {
flags is a target_ulong, which means it might only be 32 bits.
But H_GUEST_GETSET_STATE_FLAG_GUEST_WIDE has a bit set in the
upper 32 bits only. So Coverity complains about this condition
being always-zero and the body of the if being dead code.
What was the intention here?
Hi Peter,
Ideally this is intended to be running on a ppc64 where target_ulong
should be uint64_t. I guess same holds true for existing nested-hv code
as well.
Sorry, I'm afraid I misread the Coverity report here;
sorry for the confusion. The 32-vs-64 bits question is a red
herring.
What Coverity is actually pointing out is in this next bit:
+ gsr.flags |= GUEST_STATE_REQUEST_GUEST_WIDE;
+ }
+ if (flags & !H_GUEST_GETSET_STATE_FLAG_GUEST_WIDE) {
The C operator ! is the logical-NOT operator; since
H_GUEST_GETSET_STATE_FLAG_GUEST_WIDE is a non-zero value
that means that !H_GUEST_GETSET_STATE_FLAG_GUEST_WIDE is 0;
so we're testing (flags & 0), which is always false, and this
is the if() body which is dead-code as a result.
Should this be the bitwise-NOT ~ (ie "if any flag other
than this one is set"), or should this be an else clause
to the previous if() (ie "if this flag is not set") ?
Oh, this should have been bitwise-NOT, I shall send a follow-up patch
for the fix.
regards,
Harsh
+ return H_PARAMETER; /* flag not supported yet */
+ }
+
+ if (set) {
+ gsr.flags |= GUEST_STATE_REQUEST_SET;
+ }
+ return map_and_getset_state(cpu, guest, vcpuid, &gsr);
+}
thanks
-- PMM