Re: [libvirt] [PATCH qom-cpu 2/7] target-i386: Don't set any KVM flag by default if KVM is disabled

This is a cleanup that tries to solve two small issues: - We don't need a separate kvm_pv_eoi_features variable just to keep a constant calculated at compile-time, and this style would require adding a separate variable (that's declared twice because of the CONFIG_KVM ifdef) for each feature that's going to be enabled/disable by machine-type compat code. - The pc-1.3 code is setting the kvm_pv_eoi flag on cpuid_kvm_features even when KVM is disabled at runtime. This small incosistency in the cpuid_kvm_features field isn't a problem today because cpuid_kvm_features is ignored by the TCG code, but it may cause unexpected problems later when refactoring the CPUID handling code. This patch eliminates the kvm_pv_eoi_features variable and simply uses kvm_enabled() inside the enable_kvm_pv_eoi() compat function, so it enables kvm_pv_eoi only if KVM is enabled. I believe this makes the behavior of enable_kvm_pv_eoi() clearer and easier to understand.

Signed-off-by: Eduardo Habkost <ehabkost(a)redhat.com&gt; --- Cc: kvm(a)vger.kernel.org Cc: Michael S. Tsirkin <mst(a)redhat.com&gt; Cc: Gleb Natapov <gleb(a)redhat.com&gt; Cc: Marcelo Tosatti <mtosatti(a)redhat.com&gt; Changes v2: - Coding style fix Changes v3: - Eliminate #ifdef by using the fake KVM_FEATURE_PV_EOI #define --- target-i386/cpu.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 951e206..40400ac 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -164,15 +164,15 @@ static uint32_t kvm_default_features = (1 << KVM_FEATURE_CLOCKSOURCE) | (1 << KVM_FEATURE_ASYNC_PF) | (1 << KVM_FEATURE_STEAL_TIME) | (1 << KVM_FEATURE_CLOCKSOURCE_STABLE_BIT); -static const uint32_t kvm_pv_eoi_features = (0x1 << KVM_FEATURE_PV_EOI); #else static uint32_t kvm_default_features = 0; -static const uint32_t kvm_pv_eoi_features = 0; #endif void enable_kvm_pv_eoi(void) { - kvm_default_features |= kvm_pv_eoi_features; + if (kvm_enabled()) { + kvm_default_features |= (1UL << KVM_FEATURE_PV_EOI); + } } void host_cpuid(uint32_t function, uint32_t count,