[libvirt] [PATCH 5/6] qemu: add support for Direct Mode for Hyper-V Synthetic timers

[Ján Tomko]

On Thu, Jul 25, 2019 at 03:52:17PM +0200, Vitaly Kuznetsov wrote:
>QEMU-4.1 supports 'Direct Mode' for Hyper-V synthetic timers
>(hv-stimer-direct CPU flag): Windows guests can request that timer
>expiration notifications are delivered as normal interrupts (and not
>VMBus messages). This is used by Hyper-V on KVM.
>
>Signed-off-by: Vitaly Kuznetsov <vkuznets at redhat.com>
>---
> src/qemu/qemu_command.c             | 22 ++++++++++++++--
> src/qemu/qemu_process.c             | 39 +++++++++++++++++++++++++++--
> tests/qemuxml2argvdata/hyperv.args  |  4 +--
> tests/qemuxml2argvdata/hyperv.xml   |  4 ++-
> tests/qemuxml2xmloutdata/hyperv.xml |  4 ++-
> 5 files changed, 65 insertions(+), 8 deletions(-)
>
>diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>index 1cf165079f..12229e879e 100644
>--- a/src/qemu/qemu_command.c
>+++ b/src/qemu/qemu_command.c
>@@ -7096,7 +7096,7 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
>     int ret = -1;
>     virBuffer cpu_buf = VIR_BUFFER_INITIALIZER;
>     virBuffer buf = VIR_BUFFER_INITIALIZER;
>-    size_t i;
>+    size_t i, j;
>
>     if (def->cpu &&
>         (def->cpu->mode != VIR_CPU_MODE_CUSTOM || def->cpu->model)) {
>@@ -7158,7 +7158,6 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
>             case VIR_DOMAIN_HYPERV_VPINDEX:
>             case VIR_DOMAIN_HYPERV_RUNTIME:
>             case VIR_DOMAIN_HYPERV_SYNIC:
>-            case VIR_DOMAIN_HYPERV_STIMER:
>             case VIR_DOMAIN_HYPERV_RESET:
>             case VIR_DOMAIN_HYPERV_FREQUENCIES:
>             case VIR_DOMAIN_HYPERV_REENLIGHTENMENT:
>@@ -7170,6 +7169,25 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
>                                       virDomainHypervTypeToString(i));
>                 break;
>
>+            case VIR_DOMAIN_HYPERV_STIMER:
>+                if (def->hyperv_features[i] == VIR_TRISTATE_SWITCH_ON)
>+                    virBufferAsprintf(&buf, ",hv_%s",
>+                                      virDomainHypervTypeToString(i));



>+                for (j = 0; j < VIR_DOMAIN_HYPERV_STIMER_LAST; j++) {
>+                    switch ((virDomainHypervStimer) j) {
>+                    case VIR_DOMAIN_HYPERV_STIMER_DIRECT:
>+                        if (def->hyperv_stimer_features[j] == VIR_TRISTATE_SWITCH_ON)
>+                            virBufferAsprintf(&buf, ",hv_stimer_%s",
>+                                              virDomainHypervStimerTypeToString(j));
>+                        break;
>+
>+                        /* coverity[dead_error_begin] */
>+                    case VIR_DOMAIN_HYPERV_STIMER_LAST:
>+                        break;
>+                    }
>+                }

if (def->hyperv_stimer_direct == VIR_TRISTATE_SWITCH_ON)
    virBufferAddLit(&buf, "hv-stimer-direct");

>+                break;
>+
>             case VIR_DOMAIN_HYPERV_SPINLOCKS:
>                 if (def->hyperv_features[i] == VIR_TRISTATE_SWITCH_ON)
>                     virBufferAsprintf(&buf, ",hv_spinlocks=0x%x",
>diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
>index 75205bc121..0235cfd022 100644
>--- a/src/qemu/qemu_process.c
>+++ b/src/qemu/qemu_process.c
>@@ -4111,10 +4111,45 @@ qemuProcessVerifyHypervFeatures(virDomainDefPtr def,
>         rc = virCPUDataCheckFeature(cpu, cpuFeature);
>         VIR_FREE(cpuFeature);
>
>-        if (rc < 0)
>+        if (rc < 0) {
>             return -1;
>-        else if (rc == 1)
>+        } else if (rc == 1) {
>+            if ((i == VIR_DOMAIN_HYPERV_STIMER)) {
>+                size_t j;
>+

Fails compilation with my Clang:
qemu/qemu_process.c:4117:20: error: equality comparison with extraneous parentheses [-Werror,-Wparentheses-equality]
            if ((i == VIR_DOMAIN_HYPERV_STIMER)) {
                 ~~^~~~~~~~~~~~~~~~~~~~~~~~~~~
qemu/qemu_process.c:4117:20: note: remove extraneous parentheses around the comparison to silence this warning
            if ((i == VIR_DOMAIN_HYPERV_STIMER)) {
                ~  ^                          ~
qemu/qemu_process.c:4117:20: note: use '=' to turn this equality comparison into an assignment
            if ((i == VIR_DOMAIN_HYPERV_STIMER)) {
                   ^~
                   =
1 error generated.
make[5]: *** [Makefile:11191: qemu/libvirt_driver_qemu_impl_la-qemu_process.lo] Error 1

>+                for (j = 0; j < VIR_DOMAIN_HYPERV_STIMER_LAST; j++) {
>+                    switch ((virDomainHypervStimer) j) {
>+                    case VIR_DOMAIN_HYPERV_STIMER_DIRECT:
>+                        if (def->hyperv_stimer_features[j] != VIR_TRISTATE_SWITCH_ON)
>+                            continue;
>+
>+                        if (virAsprintf(&cpuFeature, "__kvm_hv_stimer_%s",
>+                                        virDomainHypervStimerTypeToString(j)) < 0)
>+                            return -1;
>+
>+                        rc = virCPUDataCheckFeature(cpu, cpuFeature);
>+                        VIR_FREE(cpuFeature);
>+
>+                        if (rc < 0)
>+                            return -1;
>+                        else if (rc == 1)
>+                            continue;
>+
>+                        virReportError(VIR_ERR_CONFIG_UNSUPPORTED,
>+                                       _("host doesn't support hyperv stimer '%s' feature"),
>+                                       virDomainHypervStimerTypeToString(i));
>+                        return -1;
>+
>+                        /* coverity[dead_error_begin] */
>+                    case VIR_DOMAIN_HYPERV_STIMER_LAST:
>+                        break;
>+                    }
>+                }
>+
>+            }
>+
>             continue;
>+        }
>
>         switch ((virDomainHyperv) i) {
>         case VIR_DOMAIN_HYPERV_RELAXED:

Jano
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