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From: | Don Slutz |
Subject: | Re: [Qemu-devel] [PATCH 2/2] target-i386: Fix default Hypervisor level for hypervisor-vendor=kvm. |
Date: | Wed, 19 Sep 2012 12:32:08 -0400 |
User-agent: | Mozilla/5.0 (X11; Linux i686 on x86_64; rv:15.0) Gecko/20120907 Thunderbird/15.0.1 |
On 09/19/12 09:20, Eduardo Habkost wrote:
On Tue, Sep 18, 2012 at 03:32:04PM -0400, Don Slutz wrote:On 09/18/12 13:00, Eduardo Habkost wrote:On Tue, Sep 18, 2012 at 10:49:53AM -0400, Don Slutz wrote:From http://lkml.indiana.edu/hypermail/linux/kernel/1205.0/00100.html EAX should be KVM_CPUID_FEATURES (0x40000001) not 0. If kvm is not configured, the additional option of hypervisor-level=1 (or hypervisor-level=0x40000001) needs to be specified to get this. --- target-i386/cpu.c | 12 +++++++++++- 1 files changed, 11 insertions(+), 1 deletions(-) diff --git a/target-i386/cpu.c b/target-i386/cpu.c index 6e43eff..d73b0a8 100644 --- a/target-i386/cpu.c +++ b/target-i386/cpu.c @@ -1248,7 +1248,12 @@ static char *x86_cpuid_get_hv_vendor(Object *obj, Error **errp) env->cpuid_hv_level == CPUID_HV_LEVEL_XEN) { pstrcpy(value, sizeof(value), "xen"); } else if (!strcmp(value, CPUID_HV_VENDOR_KVM) && - env->cpuid_hv_level == 0) { +#if defined(CONFIG_KVM) + env->cpuid_hv_level == KVM_CPUID_FEATURES +#else + env->cpuid_hv_level == 0 +#endif + ) { pstrcpy(value, sizeof(value), "kvm"); } return value; @@ -1281,6 +1286,11 @@ static void x86_cpuid_set_hv_vendor(Object *obj, const char *value, } pstrcpy(adj_value, sizeof(adj_value), CPUID_HV_VENDOR_XEN); } else if (!strcmp(value, "kvm")) { +#if defined(CONFIG_KVM) + if (env->cpuid_hv_level == 0) { + env->cpuid_hv_level = KVM_CPUID_FEATURES; + } +#endifIf CPUID[0x40000000].EAX set to 0 is documented as equivalent to having it set to 0x40000001 (KVM_CPUID_FEATURES), why the confusing checks for CONFIG_KVM? Why not always set it to KVM_CPUID_FEATURES?At line 36 of the file: #if defined(CONFIG_KVM) #include <linux/kvm_para.h> #endif So without the check you get compile failures (i386-linux-user).Right. We can't include linux/kvm_para.h on a non-Linux build host, but on the other hand I don't see any reason to not have cpuid_hv_level=0x40000001 on builds without CONFIG_KVM too. If we want to allow fake KVM CPUID leaves on non-CONFIG_KVM builds like the code above does, QEMU needs its own constant for KVM_CPUID_FEATURES/0x40000001, so it doesn't depend on the Linux header.
Will do a V2 with a local define.
I have no issue with removing the check(s) for 0. Currently hypervisor-level=0 will not force the old values; I can make a change so that works. -Don Slutz
-Don Slutz
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