Re: [PATCH] KVM: x86: don't expose syscall/sysret to intel 32-bit guest

2015-11-19 19:05 GMT+08:00 Paolo Bonzini : > > 1) Clear F(SYSCALL) in kvm_update_cpuid, like you are doing here but > only if F(LM) is already clear (in addition to the vendor being Intel). It seems that F(LM) is always set in the case of qemu-system-x86_64 w/ 32-bit guest,

Re: [PATCH] KVM: x86: don't expose syscall/sysret to intel 32-bit guest

On 25/11/2015 13:45, Wanpeng Li wrote: > 2015-11-19 19:05 GMT+08:00 Paolo Bonzini : >> >> 1) Clear F(SYSCALL) in kvm_update_cpuid, like you are doing here but >> only if F(LM) is already clear (in addition to the vendor being Intel). > > It seems that F(LM) is always set in

Re: [PATCH] KVM: x86: don't expose syscall/sysret to intel 32-bit guest

2015-11-19 19:05 GMT+08:00 Paolo Bonzini : > > > On 19/11/2015 11:45, Wanpeng li wrote: >> Intel cpu doesn't support syscall/sysret in non 64-bit mode which >> is different from AMD. Expose syscall/sysret to intel 32-bit guest >> just makes no sense and leads to #UD which will

Re: [PATCH] KVM: x86: don't expose syscall/sysret to intel 32-bit guest

On 19/11/2015 13:01, Wanpeng Li wrote: > > This is not correct. As far as I know, the SYSCALL bit is always > > present in CPUID, even if the machine is running in 32-bit mode; CPUID > > documentation (SDM Volume 2) explicitly documents bit 11 as "Bit 11: > > SYSCALL/SYSRET available in 64-bit

Re: [PATCH] KVM: x86: don't expose syscall/sysret to intel 32-bit guest

On 19/11/2015 11:45, Wanpeng li wrote: > Intel cpu doesn't support syscall/sysret in non 64-bit mode which > is different from AMD. Expose syscall/sysret to intel 32-bit guest > just makes no sense and leads to #UD which will confuse the users. > > This patch disable expose syscall/sysret to