On 2017年08月16日 17:25, Paolo Bonzini wrote:
> On 16/08/2017 03:58, Lan Tianyu wrote:
>> These CR3 VMEXITs was introduced for platform without "unrestricted guest"
>> support. This is to set ept identity table to guest CR3 in guest real
>> mode because these platforms don't support ept real mode(CR0.PE and CR0.PG
>> must be set to 1). But these VMEXITs is redundant for platforms with
>> "unrestricted guest" support.
>
> This is true, but I'm not sure it's a good idea to make things more
> complex... It is working code and is not a bottleneck anywhere.
Yes, this is just code clear up and will not affect function.
I thought this change was missed when introduced unrestricted guest support.
--
Best regards
Tianyu Lan
>
> Paolo
>
>> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
>> ---
>> arch/x86/kvm/vmx.c | 22 +++++++++++++---------
>> 1 file changed, 13 insertions(+), 9 deletions(-)
>>
>> diff --git a/arch/x86/kvm/vmx.c b/arch/x86/kvm/vmx.c
>> index 9b21b12..46dcf50 100644
>> --- a/arch/x86/kvm/vmx.c
>> +++ b/arch/x86/kvm/vmx.c
>> @@ -4221,18 +4221,20 @@ static void ept_update_paging_mode_cr0(unsigned long *hw_cr0,
>> vmx_decache_cr3(vcpu);
>> if (!(cr0 & X86_CR0_PG)) {
>> /* From paging/starting to nonpaging */
>> - vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
>> - vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) |
>> - (CPU_BASED_CR3_LOAD_EXITING |
>> - CPU_BASED_CR3_STORE_EXITING));
>> + if (!enable_unrestricted_guest)
>> + vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
>> + vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) |
>> + (CPU_BASED_CR3_LOAD_EXITING |
>> + CPU_BASED_CR3_STORE_EXITING));
>> vcpu->arch.cr0 = cr0;
>> vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
>> } else if (!is_paging(vcpu)) {
>> /* From nonpaging to paging */
>> - vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
>> - vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) &
>> - ~(CPU_BASED_CR3_LOAD_EXITING |
>> - CPU_BASED_CR3_STORE_EXITING));
>> + if (!enable_unrestricted_guest)
>> + vmcs_write32(CPU_BASED_VM_EXEC_CONTROL,
>> + vmcs_read32(CPU_BASED_VM_EXEC_CONTROL) &
>> + ~(CPU_BASED_CR3_LOAD_EXITING |
>> + CPU_BASED_CR3_STORE_EXITING));
>> vcpu->arch.cr0 = cr0;
>> vmx_set_cr4(vcpu, kvm_read_cr4(vcpu));
>> }
>> @@ -4311,7 +4313,9 @@ static void vmx_set_cr3(struct kvm_vcpu *vcpu, unsigned long cr3)
>> }
>>
>> vmx_flush_tlb(vcpu);
>> - vmcs_writel(GUEST_CR3, guest_cr3);
>> +
>> + if (!enable_unrestricted_guest || !enable_ept)
>> + vmcs_writel(GUEST_CR3, guest_cr3);
>> }
>>
>> static int vmx_set_cr4(struct kvm_vcpu *vcpu, unsigned long cr4)
>>
>
