[libvirt] [PATCH v3 4/5] qemu: add support for Direct Mode for Hyper-V Synthetic timers

[Ján Tomko]

On Tue, Aug 06, 2019 at 01:25:37PM +0200, Ján Tomko wrote:
>On Tue, Aug 06, 2019 at 07:52:35AM +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             | 12 ++++++++----
>>src/qemu/qemu_process.c             | 20 ++++++++++++++++++--
>>tests/qemuxml2argvdata/hyperv.args  |  4 ++--
>>tests/qemuxml2argvdata/hyperv.xml   |  4 +++-
>>tests/qemuxml2xmloutdata/hyperv.xml |  4 +++-
>>5 files changed, 34 insertions(+), 10 deletions(-)
>>
>>diff --git a/src/qemu/qemu_command.c b/src/qemu/qemu_command.c
>>index c8494de785..af913dba34 100644
>>--- a/src/qemu/qemu_command.c
>>+++ b/src/qemu/qemu_command.c
>>@@ -7152,10 +7152,10 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
>>    }
>>
>>    if (def->features[VIR_DOMAIN_FEATURE_HYPERV] == VIR_TRISTATE_SWITCH_ON) {
>>-        const char *hvPrefix = "hv-";
>>+        const char *hvDelimiter = "-";
>>
>>        if (!virQEMUCapsGet(qemuCaps, QEMU_CAPS_CANONICAL_CPU_FEATURES))
>>-            hvPrefix = "hv_";
>>+            hvDelimiter = "_";
>>
>>        for (i = 0; i < VIR_DOMAIN_HYPERV_LAST; i++) {
>>            switch ((virDomainHyperv) i) {
>>@@ -7172,9 +7172,13 @@ qemuBuildCpuCommandLine(virCommandPtr cmd,
>>            case VIR_DOMAIN_HYPERV_IPI:
>>            case VIR_DOMAIN_HYPERV_EVMCS:
>>                if (def->hyperv_features[i] == VIR_TRISTATE_SWITCH_ON)
>>-                    virBufferAsprintf(&buf, ",%s%s",
>>-                                      hvPrefix,
>>+                    virBufferAsprintf(&buf, ",hv%s%s",
>>+                                      hvDelimiter,
>>                                      virDomainHypervTypeToString(i));
>>+                if ((i == VIR_DOMAIN_HYPERV_STIMER) &&
>>+                    (def->hyperv_stimer_direct == VIR_TRISTATE_SWITCH_ON))
>>+                    virBufferAsprintf(&buf, ",hv%sstimer%sdirect", hvDelimiter,
>>+                                      hvDelimiter);
>
>IIUC this feature will be introduced in QEMU 4.1.0 which is the one
>where we stop using the aliases with underscores, so this can be
>",hv-stimer-direct" and the hvDelimiter changes are not needed.
>

Or even the VIR_CPU_x86_HV_STIMER_DIRECT string instead.

One more thing, qemuxml2argvtest is using DO_TEST:
    DO_TEST("hyperv", NONE);
    DO_TEST("hyperv-off", NONE);
    DO_TEST("hyperv-panic", NONE);
which manually enumarate the used QEMU capabilities (although there are
none here)

DO_TEST_CAPS_LATEST is the way to test against QEMU capabilites
gathered from a real binary - if you use that macro for testing,
it will have the QEMU_CAPS_CANONICAL_CPU_FEATURES capability and all the
included features will use '-' instead of '_' as the separator.

Jano

>With that changed:
>
>Reviewed-by: Ján Tomko <jtomko at redhat.com>
>
>Jano



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