Re: [RFC PATCH v1 02/10] KVM: SVM: Add KVM_SEND_UPDATE_DATA command

Singh, Brijesh
2019-04-29T16:54:18Z

On 4/26/19 3:31 PM, Lendacky, Thomas wrote:
...

>>
>> static unsigned int max_sev_asid;
>> static unsigned int min_sev_asid;
>> +static unsigned long me_mask;
>
> sev_me_mask ?
>

Agreed.

>> static unsigned long *sev_asid_bitmap;
>> #define __sme_page_pa(x) __sme_set(page_to_pfn(x) << PAGE_SHIFT)
>>
>> @@ -1216,15 +1217,21 @@ static int avic_ga_log_notifier(u32 ga_tag)
>> static __init int sev_hardware_setup(void)
>> {
>> struct sev_user_data_status *status;
>> + int eax, ebx;
>> int rc;
>>
>> - /* Maximum number of encrypted guests supported simultaneously */
>> - max_sev_asid = cpuid_ecx(0x8000001F);
>> + /*
>> + * Query the memory encryption information.
>> + * EBX: Bit 0:5 Pagetable bit position used to indicate encryption (aka Cbit).
>> + * ECX: Maximum number of encrypted guests supported simultaneously.
>> + * EDX: Minimum ASID value that should be used for SEV guest.
>> + */
>> + cpuid(0x8000001f, &eax, &ebx, &max_sev_asid, &min_sev_asid);
>>
>> if (!max_sev_asid)
>> return 1;
>>
>> - /* Minimum ASID value that should be used for SEV guest */
>> + me_mask = 1UL << (ebx & 0x3f);
>> min_sev_asid = cpuid_edx(0x8000001F);
>
> You can remove this since you obtained it with the cpuid() call above.
>

I thought I removed it but.. I will take care in next rev.

>>
>> /* Initialize SEV ASID bitmap */
>> @@ -7053,6 +7060,118 @@ static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
>> return ret;
>> }
>>
>> +static int sev_send_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
>> +{
>> + struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
>> + struct sev_data_send_update_data *data;
>> + struct kvm_sev_send_update_data params;
>> + void *hdr = NULL, *trans_data = NULL;
>> + struct page **guest_page = NULL;
>> + unsigned long n;
>> + int ret, offset;
>> +
>> + if (!sev_guest(kvm))
>> + return -ENOTTY;
>> +
>> + if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data,
>> + sizeof(struct kvm_sev_send_update_data)))
>> + return -EFAULT;
>> +
>> + data = kzalloc(sizeof(*data), GFP_KERNEL);
>> + if (!data)
>> + return -ENOMEM;
>> +
>> + /* userspace wants to query either header or trans length */
>> + if (!params.trans_len || !params.hdr_len)
>> + goto cmd;
>> +
>> + ret = -EINVAL;
>> + if (!params.trans_uaddr || !params.guest_uaddr ||
>> + !params.guest_len || !params.hdr_uaddr)
>> + goto e_free;
>> +
>> + /* Check if we are crossing the page boundry */
>> + ret = -EINVAL;
>> + offset = params.guest_uaddr & (PAGE_SIZE - 1);
>> + if ((params.guest_len + offset > PAGE_SIZE))
>> + goto e_free;
>> +
>> + ret = -ENOMEM;
>> + hdr = kmalloc(params.hdr_len, GFP_KERNEL);
>> + if (!hdr)
>> + goto e_free;
>> +
>> + data->hdr_address = __psp_pa(hdr);
>> + data->hdr_len = params.hdr_len;
>> +
>> + ret = -ENOMEM;
>> + trans_data = kmalloc(params.trans_len, GFP_KERNEL);
>> + if (!trans_data)
>> + goto e_free;
>> +
>> + data->trans_address = __psp_pa(trans_data);
>> + data->trans_len = params.trans_len;
>> +
>> + /* Pin guest memory */
>> + ret = -EFAULT;
>> + guest_page = sev_pin_memory(kvm, params.guest_uaddr & PAGE_MASK,
>> + PAGE_SIZE, &n, 0);
>> + if (!guest_page)
>> + goto e_free;
>> +
>> + data->guest_address = __sme_page_pa(guest_page[0]) + offset;
>
> If the C-bit needs to be set regardless below, then you don't need the
> __sme version of this.
>

Noted.