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
Thanks,
Tom
> > sev_enabled = sev_supported;
> sev_es_enabled = sev_es_supported;
