linux-kernel - Re: [PATCH 07/13] KVM: x86: API changes for SMM support

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Date:	Mon, 04 May 2015 18:02:56 +0200
From:	Paolo Bonzini <pbonzini@...hat.com>
To:	Radim Krčmář <rkrcmar@...hat.com>
CC:	linux-kernel@...r.kernel.org, kvm@...r.kernel.org, bsd@...hat.com,
	guangrong.xiao@...ux.intel.com,
	Yang Zhang <yang.z.zhang@...el.com>, wanpeng.li@...ux.intel.com
Subject: Re: [PATCH 07/13] KVM: x86: API changes for SMM support



On 04/05/2015 17:37, Radim Krčmář wrote:
> 2015-04-30 13:36+0200, Paolo Bonzini:
>> This patch includes changes to the external API for SMM support.
>> All the changes are predicated by the availability of a new
>> capability, KVM_CAP_X86_SMM, which is added at the end of the
>> patch series.
>>
>> Signed-off-by: Paolo Bonzini <pbonzini@...hat.com>
>> ---
>> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
>> @@ -820,11 +820,19 @@ struct kvm_vcpu_events {
>>  	} nmi;
>>  	__u32 sipi_vector;
>>  	__u32 flags;
>> +	struct {
>> +		__u8 smm;
> 
> 34.3.1 Entering SMM:
>   Subsequent SMI requests are not acknowledged while the processor is in
>   SMM. The first SMI interrupt request that occurs while the processor
>   is in SMM (that is, after SMM has been acknowledged to external
>   hardware) is latched and serviced when the processor exits SMM with
>   the RSM instruction. The processor will latch only one SMI while in
>   SMM.
> 
> The final code doesn't handle pending SMI's at all, so we'll need to
> store it somewhere and expose to userspace here.

Right, and I can add this to the slow path I already have for SMM exits:

+		if (ctxt->emul_flags != vcpu->arch.hflags) {
+			vcpu->arch.hflags = ctxt->emul_flags;
+			kvm_mmu_reset_context(vcpu);
+		}

Paolo

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