| Message ID | 1357582848-16575-3-git-send-email-ehabkost@redhat.com |
|---|---|
| State | New |
| Headers | show |
On Mon, 7 Jan 2013 16:20:43 -0200 Eduardo Habkost <ehabkost@redhat.com> wrote: > 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. Subj doesn't match what patch actually does. Have you meant "Don't set kvm_pv_eoi flag by default if KVM is disabled"? Although "eliminate kvm_pv_eoi_features variable" might better describe what patch is doing. > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > --- > Cc: kvm@vger.kernel.org > Cc: Michael S. Tsirkin <mst@redhat.com> > Cc: Gleb Natapov <gleb@redhat.com> > Cc: Marcelo Tosatti <mtosatti@redhat.com> > > 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,
On Wed, Jan 09, 2013 at 10:46:12AM +0100, Igor Mammedov wrote: > On Mon, 7 Jan 2013 16:20:43 -0200 > Eduardo Habkost <ehabkost@redhat.com> wrote: > > > 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. > > Subj doesn't match what patch actually does. > Have you meant "Don't set kvm_pv_eoi flag by default if KVM is disabled"? > Although "eliminate kvm_pv_eoi_features variable" might better describe what > patch is doing. True. The other flags in kvm_default_features may be already set and will be copied to cpuid_kvm_features even if kvm_enabled() is false. I had a previous version of this patch that also changed the code using kvm_default_features to check kvm_enabled(), but I removed that part and kept only the kvm_pv_eoi_features variable removal. Andreas, please ignore this patch (it is not necessary anymore as this series doesn't include machine-type compatibility code for kvm_mmu). Patches 2-7 don't depend on this patch and should apply cleanly without it. I will send a new version later, probably with a separate patch to ignore kvm_default_features if kvm_enabled() is false (so there's no need to even check kvm_enabled() inside enable_kvm_pv_eoi()). > > > > > Signed-off-by: Eduardo Habkost <ehabkost@redhat.com> > > --- > > Cc: kvm@vger.kernel.org > > Cc: Michael S. Tsirkin <mst@redhat.com> > > Cc: Gleb Natapov <gleb@redhat.com> > > Cc: Marcelo Tosatti <mtosatti@redhat.com> > > > > 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, >
On Wed, Jan 09, 2013 at 09:41:37AM -0200, Eduardo Habkost wrote: [...] > Andreas, please ignore this patch (it is not necessary anymore as this > series doesn't include machine-type compatibility code for kvm_mmu). > Patches 2-7 don't depend on this patch and should apply cleanly without > it. I mean: patches 1 and 3-7 don't depend on this patch and can be applied cleanly without it.
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,
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@redhat.com> --- Cc: kvm@vger.kernel.org Cc: Michael S. Tsirkin <mst@redhat.com> Cc: Gleb Natapov <gleb@redhat.com> Cc: Marcelo Tosatti <mtosatti@redhat.com> 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(-)