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SubjectRe: [RFC Part2 PATCH v3 14/26] KVM: SVM: VMRUN should use assosiated ASID when SEV is enabled
On Mon, Jul 24, 2017 at 03:02:51PM -0500, Brijesh Singh wrote:
> SEV hardware uses ASIDs to associate memory encryption key with the
> guest VMs. During the guest creation time, we use SEV_CMD_ACTIVATE

"VM"

> command to bind a particular ASID to the guest. Lets make sure that
> VMCB is programmed with the binded ASID before a VMRUN.

"the VMCB" binded? you mean "bound"

>
> Signed-off-by: Brijesh Singh <brijesh.singh@amd.com>
> ---
> arch/x86/kvm/svm.c | 50 +++++++++++++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 49 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
> index e99a572..72f7c27 100644
> --- a/arch/x86/kvm/svm.c
> +++ b/arch/x86/kvm/svm.c
> @@ -213,6 +213,9 @@ struct vcpu_svm {
> */
> struct list_head ir_list;
> spinlock_t ir_list_lock;
> +
> + /* which host cpu was used for running this vcpu */

s/cpu/CPU/

> + unsigned int last_cpuid;

... and since it is a CPU, then "last_cpu" I guess.

> };
>
> /*
> @@ -573,6 +576,8 @@ struct svm_cpu_data {
> struct kvm_ldttss_desc *tss_desc;
>
> struct page *save_area;
> +
> + struct vmcb **sev_vmcbs; /* index = sev_asid, value = vmcb pointer */

Put that comment above it.

> static DEFINE_PER_CPU(struct svm_cpu_data *, svm_data);
> @@ -886,6 +891,7 @@ static void svm_cpu_uninit(int cpu)
> return;
>
> per_cpu(svm_data, raw_smp_processor_id()) = NULL;
> + kfree(sd->sev_vmcbs);
> __free_page(sd->save_area);
> kfree(sd);
> }
> @@ -904,6 +910,14 @@ static int svm_cpu_init(int cpu)
> if (!sd->save_area)
> goto err_1;
>
> + if (svm_sev_enabled()) {
> + sd->sev_vmcbs = kmalloc((max_sev_asid + 1) * sizeof(void *),
> + GFP_KERNEL);

You can let that line stick out.

> + r = -ENOMEM;

That assignment usually is done before the call. I know, this function
does it differently but you can fix it up while you're touching it.

> + if (!sd->sev_vmcbs)
> + goto err_1;
> + }
> +
> per_cpu(svm_data, cpu) = sd;
>
> return 0;
> @@ -4442,12 +4456,40 @@ static void reload_tss(struct kvm_vcpu *vcpu)
> load_TR_desc();
> }
>
> +static void pre_sev_run(struct vcpu_svm *svm)
> +{
> + int cpu = raw_smp_processor_id();
> + int asid = sev_get_asid(svm->vcpu.kvm);
> + struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
> +
> + /* Assign the asid allocated with this SEV guest */
> + svm->vmcb->control.asid = asid;
> +
> + /*
> + * Flush guest TLB:
> + *
> + * 1) when different VMCB for the same ASID is to be run on the same host CPU.
> + * 2) or this VMCB was executed on different host cpu in previous VMRUNs.

s/cpu/CPU/

> + */
> + if (sd->sev_vmcbs[asid] == svm->vmcb &&
> + svm->last_cpuid == cpu)
> + return;
> +
> + svm->last_cpuid = cpu;
> + sd->sev_vmcbs[asid] = svm->vmcb;
> + svm->vmcb->control.tlb_ctl = TLB_CONTROL_FLUSH_ASID;
> + mark_dirty(svm->vmcb, VMCB_ASID);
> +}
> +
> static void pre_svm_run(struct vcpu_svm *svm)
> {
> int cpu = raw_smp_processor_id();
>
> struct svm_cpu_data *sd = per_cpu(svm_data, cpu);
>
> + if (sev_guest(svm->vcpu.kvm))
> + return pre_sev_run(svm);

Just pass @cpu here so that you don't have to do raw_smp_processor_id()
again above.

--
Regards/Gruss,
Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
--

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