Merge tag 'kvm-x86-svm-6.9' of https://github.com/kvm-x86/linux into HEAD

[sfrench/cifs-2.6.git] / arch / x86 / kvm / svm / sev.c

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index ae0ac12382b9278732fc89d4ef00a5f84866f8c0..e5a4d9b0e79fd23e2dfc8224aa7a89d3b243c103 100644 (file)
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -84,9 +84,10 @@ struct enc_region {
 };
 
 /* Called with the sev_bitmap_lock held, or on shutdown  */
-static int sev_flush_asids(int min_asid, int max_asid)
+static int sev_flush_asids(unsigned int min_asid, unsigned int max_asid)
 {
-       int ret, asid, error = 0;
+       int ret, error = 0;
+       unsigned int asid;
 
        /* Check if there are any ASIDs to reclaim before performing a flush */
        asid = find_next_bit(sev_reclaim_asid_bitmap, nr_asids, min_asid);
@@ -116,7 +117,7 @@ static inline bool is_mirroring_enc_context(struct kvm *kvm)
 }
 
 /* Must be called with the sev_bitmap_lock held */
-static bool __sev_recycle_asids(int min_asid, int max_asid)
+static bool __sev_recycle_asids(unsigned int min_asid, unsigned int max_asid)
 {
        if (sev_flush_asids(min_asid, max_asid))
                return false;
@@ -143,8 +144,20 @@ static void sev_misc_cg_uncharge(struct kvm_sev_info *sev)
 
 static int sev_asid_new(struct kvm_sev_info *sev)
 {
-       int asid, min_asid, max_asid, ret;
+       /*
+        * 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;
        bool retry = true;
+       int ret;
+
+       if (min_asid > max_asid)
+               return -ENOTTY;
 
        WARN_ON(sev->misc_cg);
        sev->misc_cg = get_current_misc_cg();
@@ -157,12 +170,6 @@ static int sev_asid_new(struct kvm_sev_info *sev)
 
        mutex_lock(&sev_bitmap_lock);
 
-       /*
-        * 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.
-        */
-       min_asid = sev->es_active ? 1 : min_sev_asid;
-       max_asid = sev->es_active ? min_sev_asid - 1 : max_sev_asid;
 again:
        asid = find_next_zero_bit(sev_asid_bitmap, max_asid + 1, min_asid);
        if (asid > max_asid) {
@@ -179,7 +186,8 @@ again:
 
        mutex_unlock(&sev_bitmap_lock);
 
-       return asid;
+       sev->asid = asid;
+       return 0;
 e_uncharge:
        sev_misc_cg_uncharge(sev);
        put_misc_cg(sev->misc_cg);
@@ -187,7 +195,7 @@ e_uncharge:
        return ret;
 }
 
-static int sev_get_asid(struct kvm *kvm)
+static unsigned int sev_get_asid(struct kvm *kvm)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
 
@@ -247,21 +255,19 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
        struct sev_platform_init_args init_args = {0};
-       int asid, ret;
+       int ret;
 
        if (kvm->created_vcpus)
                return -EINVAL;
 
-       ret = -EBUSY;
        if (unlikely(sev->active))
-               return ret;
+               return -EINVAL;
 
        sev->active = true;
        sev->es_active = argp->id == KVM_SEV_ES_INIT;
-       asid = sev_asid_new(sev);
-       if (asid < 0)
+       ret = sev_asid_new(sev);
+       if (ret)
                goto e_no_asid;
-       sev->asid = asid;
 
        init_args.probe = false;
        ret = sev_platform_init(&init_args);
@@ -287,8 +293,8 @@ e_no_asid:
 
 static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
 {
+       unsigned int asid = sev_get_asid(kvm);
        struct sev_data_activate activate;
-       int asid = sev_get_asid(kvm);
        int ret;
 
        /* activate ASID on the given handle */
@@ -2240,8 +2246,10 @@ void __init sev_hardware_setup(void)
                goto out;
        }
 
-       sev_asid_count = max_sev_asid - min_sev_asid + 1;
-       WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV, sev_asid_count));
+       if (min_sev_asid <= max_sev_asid) {
+               sev_asid_count = max_sev_asid - min_sev_asid + 1;
+               WARN_ON_ONCE(misc_cg_set_capacity(MISC_CG_RES_SEV, sev_asid_count));
+       }
        sev_supported = true;
 
        /* SEV-ES support requested? */
@@ -2272,7 +2280,9 @@ void __init sev_hardware_setup(void)
 out:
        if (boot_cpu_has(X86_FEATURE_SEV))
                pr_info("SEV %s (ASIDs %u - %u)\n",
-                       sev_supported ? "enabled" : "disabled",
+                       sev_supported ? min_sev_asid <= max_sev_asid ? "enabled" :
+                                                                      "unusable" :
+                                                                      "disabled",
                        min_sev_asid, max_sev_asid);
        if (boot_cpu_has(X86_FEATURE_SEV_ES))
                pr_info("SEV-ES %s (ASIDs %u - %u)\n",
@@ -2320,7 +2330,7 @@ int sev_cpu_init(struct svm_cpu_data *sd)
  */
 static void sev_flush_encrypted_page(struct kvm_vcpu *vcpu, void *va)
 {
-       int asid = to_kvm_svm(vcpu->kvm)->sev_info.asid;
+       unsigned int asid = sev_get_asid(vcpu->kvm);
 
        /*
         * Note!  The address must be a kernel address, as regular page walk
@@ -2638,7 +2648,7 @@ void sev_es_unmap_ghcb(struct vcpu_svm *svm)
 void pre_sev_run(struct vcpu_svm *svm, int cpu)
 {
        struct svm_cpu_data *sd = per_cpu_ptr(&svm_data, cpu);
-       int asid = sev_get_asid(svm->vcpu.kvm);
+       unsigned int asid = sev_get_asid(svm->vcpu.kvm);
 
        /* Assign the asid allocated with this SEV guest */
        svm->asid = asid;