Re: [PATCH 1/4] stubs for xsavec support

[Paolo Bonzini <pbonzini@redhat.com>]

On 06/02/2015 20:40, Jan Kiszka wrote:
> On 2015-02-02 10:05, Paolo Bonzini wrote:
>>
>>
>> On 02/02/2015 08:04, Jan Kiszka wrote:
>>>>> +#if X86_FEATURE_XSAVEOPT < 10 * 32
>>>>> +#undef X86_FEATURE_XSAVEOPT
>>>>> +#endif
>>>>> +#define X86_FEATURE_XSAVEOPT	(10*32+0) /* XSAVEOPT instruction */
>>> This causes redefinition warnings if the condition is not met. Was the
>>> plan to put the define before the #endif?
>>
>> The plan was to match the kernel's definition, which however has a space:
>>
>> #define X86_FEATURE_XSAVEOPT	(10*32+ 0)
>>
>> But putting the define before the #endif also works.
> 
> Finally got my buildbot working again: There are some open issues, maybe
> you can have a look at http://buildbot.kiszka.org/kvm-kmod/waterfall,
> next branch. At least the 3.17 thing requires fixing but may require
> more than a #define.

Why is APICv crippled in kvm-kmod even for newer kernels?

If all that's needed is "make it compile with 3.9 and earlier",
you can do something like this:

diff --git a/sync b/sync
index 3086b70..36bed39 100755
--- a/sync
+++ b/sync
@@ -341,13 +341,18 @@ def hack_content(fname, data):
         if line == '\tif (!cpu_has_vmx_apicv())':
             w('#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,10,0)')
             w(line)
+            w('#else')
+            w('if (1)')
             line = '#endif'
         if line == '#if IS_ENABLED(CONFIG_KVM)':
             line = '#if 1'
-        if line == '\t\tapic->send_IPI_mask(get_cpu_mask(vcpu->cpu),':
-            line = '\t\t;'
-        if line == '\t\t\t\tPOSTED_INTR_VECTOR);':
-            line = ''
+        if match(r'^\t+apic->send_IPI_mask\(get_cpu_mask\(vcpu->cpu\),$'):
+            w('#if LINUX_VERSION_CODE < KERNEL_VERSION(3,10,0)')
+	    w('\t\t;')
+	    w('#else')
+        if match(r'^\t+POSTED_INTR_VECTOR\);$'):
+            w(line)
+            line = '#endif'
         if line == '\tif (!static_cpu_has_bug(X86_BUG_AMD_TLB_MMATCH))':
             w('#if LINUX_VERSION_CODE >= KERNEL_VERSION(3,10,0)')
             w(line)

Paolo