2015-05-27 19:05+0200, Paolo Bonzini:
> The big ugly one. This patch adds support for switching in and out of
> system management mode, respectively upon receiving KVM_REQ_SMI and upon
> executing a RSM instruction. Both 32- and 64-bit formats are supported
> for the SMM state save area.
>
> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx>
> ---
> RFC->v1: shift access rights left by 8 for 32-bit format
> move tracepoint to kvm_set_hflags
> fix NMI handling
> ---
> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
> static void process_smi(struct kvm_vcpu *vcpu)
> {
> + struct kvm_segment cs, ds;
> + char buf[512];
> + u32 cr0;
> + int r;
> +
> if (is_smm(vcpu)) {
> vcpu->arch.smi_pending = true;
> return;
> }
>
> - printk_once(KERN_DEBUG "Ignoring guest SMI\n");
> + trace_kvm_enter_smm(vcpu->vcpu_id, vcpu->arch.smbase, true);
> + vcpu->arch.hflags |= HF_SMM_MASK;
> + memset(buf, 0, 512);
> + if (guest_cpuid_has_longmode(vcpu))
> + process_smi_save_state_64(vcpu, buf);
> + else
> + process_smi_save_state_32(vcpu, buf);
> +
> + r = kvm_write_guest(vcpu->kvm, vcpu->arch.smbase + 0xfe00, buf, sizeof(buf));
The state is saved in SMRAM, but we are accessing it using the non-SMM
address space ... how did it pass testing?
(Restore is using SMM address space, so I'm guessing that the mapping
from QEMU wasn't really utilizing two separate address spaces.)
> + if (r < 0)
> + return;
And if we fail to write it, is there other option than throwing an error
to userspace? (Unset HF_SMM_MASK and pretend that nothing happened
doesn't find much support in docs.)
Thanks.
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