On 6/3/2025 10:52 AM, Tom Lendacky wrote:
> On 5/19/25 18:57, Ashish Kalra wrote:
>> From: Ashish Kalra <ashish.kalra@xxxxxxx>
>>
>> Introduce new min, max sev_es_asid and sev_snp_asid variables.
>>
>> The new {min,max}_{sev_es,snp}_asid variables along with existing
>> {min,max}_sev_asid variable simplifies partitioning of the
>> SEV and SEV-ES+ ASID space.
>>
>> Suggested-by: Sean Christopherson <seanjc@xxxxxxxxxx>
>> Signed-off-by: Ashish Kalra <ashish.kalra@xxxxxxx>
>> ---
>> arch/x86/kvm/svm/sev.c | 37 ++++++++++++++++++++++++++++---------
>> 1 file changed, 28 insertions(+), 9 deletions(-)
>>
>> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
>> index dea9480b9ff6..383db1da8699 100644
>> --- a/arch/x86/kvm/svm/sev.c
>> +++ b/arch/x86/kvm/svm/sev.c
>> @@ -85,6 +85,10 @@ static DECLARE_RWSEM(sev_deactivate_lock);
>> static DEFINE_MUTEX(sev_bitmap_lock);
>> unsigned int max_sev_asid;
>> static unsigned int min_sev_asid;
>> +static unsigned int max_sev_es_asid;
>> +static unsigned int min_sev_es_asid;
>> +static unsigned int max_snp_asid;
>> +static unsigned int min_snp_asid;
>> static unsigned long sev_me_mask;
>> static unsigned int nr_asids;
>> static unsigned long *sev_asid_bitmap;
>> @@ -172,20 +176,32 @@ static void sev_misc_cg_uncharge(struct kvm_sev_info *sev)
>> misc_cg_uncharge(type, sev->misc_cg, 1);
>> }
>>
>> -static int sev_asid_new(struct kvm_sev_info *sev)
>> +static int sev_asid_new(struct kvm_sev_info *sev, unsigned long vm_type)
>> {
>> /*
>> * SEV-enabled guests must use asid from min_sev_asid to max_sev_asid.
>> * SEV-ES-enabled guest can use from 1 to min_sev_asid - 1.
>> - * Note: min ASID can end up larger than the max if basic SEV support is
>> - * effectively disabled by disallowing use of ASIDs for SEV guests.
>> */
>> - unsigned int min_asid = sev->es_active ? 1 : min_sev_asid;
>> - unsigned int max_asid = sev->es_active ? min_sev_asid - 1 : max_sev_asid;
>> - unsigned int asid;
>> + unsigned int min_asid, max_asid, asid;
>> bool retry = true;
>> int ret;
>>
>> + if (vm_type == KVM_X86_SNP_VM) {
>> + min_asid = min_snp_asid;
>> + max_asid = max_snp_asid;
>> + } else if (sev->es_active) {
>> + min_asid = min_sev_es_asid;
>> + max_asid = max_sev_es_asid;
>> + } else {
>> + min_asid = min_sev_asid;
>> + max_asid = max_sev_asid;
>> + }
>> +
>> + /*
>> + * The min ASID can end up larger than the max if basic SEV support is
>> + * effectively disabled by disallowing use of ASIDs for SEV guests.
>> + */
>> +
>
> Remove blank line.
>
>> if (min_asid > max_asid)
>> return -ENOTTY;
>>
>> @@ -439,7 +455,7 @@ static int __sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp,
>> if (vm_type == KVM_X86_SNP_VM)
>> sev->vmsa_features |= SVM_SEV_FEAT_SNP_ACTIVE;
>>
>> - ret = sev_asid_new(sev);
>> + ret = sev_asid_new(sev, vm_type);
>> if (ret)
>> goto e_no_asid;
>>
>> @@ -3029,6 +3045,9 @@ void __init sev_hardware_setup(void)
>> goto out;
>> }
>>
>> + min_sev_es_asid = min_snp_asid = 1;
>> + max_sev_es_asid = max_snp_asid = min_sev_asid - 1;
>
> Should these be moved to after the min_sev_asid == 1 check ...
>
>> +
>> /* Has the system been allocated ASIDs for SEV-ES? */
>> if (min_sev_asid == 1)
>> goto out;
>> @@ -3048,11 +3067,11 @@ void __init sev_hardware_setup(void)
>> if (boot_cpu_has(X86_FEATURE_SEV_ES))
>> pr_info("SEV-ES %s (ASIDs %u - %u)\n",
>> str_enabled_disabled(sev_es_supported),
>> - min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
>> + min_sev_es_asid, max_sev_es_asid);
>
> ... so that this becomes 0 and 0 if min_sev_asid == 1 ? (like before)
>
>> if (boot_cpu_has(X86_FEATURE_SEV_SNP))
>> pr_info("SEV-SNP %s (ASIDs %u - %u)\n",
>> str_enabled_disabled(sev_snp_supported),
>> - min_sev_asid > 1 ? 1 : 0, min_sev_asid - 1);
>> + min_snp_asid, max_snp_asid);
>
> Ditto
>
Yes that makes sense.
Thanks,
Ashish
> Thanks,
> Tom
>
>> > sev_enabled = sev_supported;
>> sev_es_enabled = sev_es_supported;
