[PATCH v2 1/1] spapr_caps.c: check user input before warning about TCG only caps

[Daniel Henrique Barboza]

Commit 006e9d361869 added warning messages for cap-cfpc, cap-ibs and
cap-sbbc when enabled under TCG. Commit 8ff43ee404d3 did the same thing
when introducing cap-ccf-assist.

These warning messages, although benign to the machine launch, can make
users a bit confused. E.g:

$ sudo ./ppc64-softmmu/qemu-system-ppc64
qemu-system-ppc64: warning: TCG doesn't support requested feature, 
cap-cfpc=workaround
qemu-system-ppc64: warning: TCG doesn't support requested feature, 
cap-sbbc=workaround
qemu-system-ppc64: warning: TCG doesn't support requested feature, 
cap-ibs=workaround
qemu-system-ppc64: warning: TCG doesn't support requested feature, 
cap-ccf-assist=on

We're complaining about "TCG doesn't support requested feature" when the
user didn't request any of those caps in the command line.

Check if these caps were set in the command line before sending an user
warning.

Signed-off-by: Daniel Henrique Barboza <danielhb413@gmail.com>
---
 hw/ppc/spapr_caps.c | 47 ++++++++++++++++++++++++++++++++++-----------
 1 file changed, 36 insertions(+), 11 deletions(-)

diff --git a/hw/ppc/spapr_caps.c b/hw/ppc/spapr_caps.c
index 9341e9782a..629c24a96d 100644
--- a/hw/ppc/spapr_caps.c
+++ b/hw/ppc/spapr_caps.c
@@ -244,9 +244,15 @@ static void cap_safe_cache_apply(SpaprMachineState *spapr, 
uint8_t val,
     uint8_t kvm_val =  kvmppc_get_cap_safe_cache();
 
     if (tcg_enabled() && val) {
-        /* TCG only supports broken, allow other values and print a warning */
-        warn_report("TCG doesn't support requested feature, cap-cfpc=%s",
-                    cap_cfpc_possible.vals[val]);
+        /*
+         * TCG only supports broken, allow other values and print a warning
+         * in case the user attempted to set a different value in the command
+         * line.
+         */
+        if (spapr->cmd_line_caps[SPAPR_CAP_CFPC] != SPAPR_CAP_BROKEN) {
+            warn_report("TCG doesn't support requested feature, cap-cfpc=%s",
+                        cap_cfpc_possible.vals[val]);
+        }
     } else if (kvm_enabled() && (val > kvm_val)) {
         error_setg(errp,
                    "Requested safe cache capability level not supported by 
KVM");
@@ -269,9 +275,15 @@ static void cap_safe_bounds_check_apply(SpaprMachineState 
*spapr, uint8_t val,
     uint8_t kvm_val =  kvmppc_get_cap_safe_bounds_check();
 
     if (tcg_enabled() && val) {
-        /* TCG only supports broken, allow other values and print a warning */
-        warn_report("TCG doesn't support requested feature, cap-sbbc=%s",
-                    cap_sbbc_possible.vals[val]);
+        /*
+         * TCG only supports broken, allow other values and print a warning
+         * in case the user attempted to set a different value in the command
+         * line.
+         */
+        if (spapr->cmd_line_caps[SPAPR_CAP_SBBC] != SPAPR_CAP_BROKEN) {
+            warn_report("TCG doesn't support requested feature, cap-sbbc=%s",
+                        cap_sbbc_possible.vals[val]);
+        }
     } else if (kvm_enabled() && (val > kvm_val)) {
         error_setg(errp,
 "Requested safe bounds check capability level not supported by KVM");
@@ -297,9 +309,15 @@ static void 
cap_safe_indirect_branch_apply(SpaprMachineState *spapr,
     uint8_t kvm_val = kvmppc_get_cap_safe_indirect_branch();
 
     if (tcg_enabled() && val) {
-        /* TCG only supports broken, allow other values and print a warning */
-        warn_report("TCG doesn't support requested feature, cap-ibs=%s",
-                    cap_ibs_possible.vals[val]);
+        /*
+         * TCG only supports broken, allow other values and print a warning
+         * in case the user attempted to set a different value in the command
+         * line.
+         */
+        if (spapr->cmd_line_caps[SPAPR_CAP_IBS] != SPAPR_CAP_BROKEN) {
+            warn_report("TCG doesn't support requested feature, cap-ibs=%s",
+                        cap_ibs_possible.vals[val]);
+        }
     } else if (kvm_enabled() && (val > kvm_val)) {
         error_setg(errp,
 "Requested safe indirect branch capability level not supported by KVM");
@@ -483,8 +501,15 @@ static void cap_ccf_assist_apply(SpaprMachineState *spapr, 
uint8_t val,
     uint8_t kvm_val = kvmppc_get_cap_count_cache_flush_assist();
 
     if (tcg_enabled() && val) {
-        /* TCG doesn't implement anything here, but allow with a warning */
-        warn_report("TCG doesn't support requested feature, 
cap-ccf-assist=on");
+        /*
+         * TCG doesn't implement anything here, but allow with a warning
+         * in case the user attempted to set a different value in the command
+         * line.
+         */
+        if (spapr->cmd_line_caps[SPAPR_CAP_CCF_ASSIST] != SPAPR_CAP_OFF) {
+            warn_report("TCG doesn't support requested feature, "
+                        "cap-ccf-assist=on");
+        }
     } else if (kvm_enabled() && (val > kvm_val)) {
         uint8_t kvm_ibs = kvmppc_get_cap_safe_indirect_branch();
 
-- 
2.26.2