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Diffstat (limited to 'arch/x86/kvm/svm/sev.c')
-rw-r--r--arch/x86/kvm/svm/sev.c52
1 files changed, 33 insertions, 19 deletions
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 1226bb2151..86088d1250 100644
--- 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) {
@@ -187,7 +194,7 @@ 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;
@@ -284,8 +291,8 @@ 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 */
@@ -2196,10 +2203,13 @@ void __init sev_hardware_setup(void)
/*
* SEV must obviously be supported in hardware. Sanity check that the
* CPU supports decode assists, which is mandatory for SEV guests to
- * support instruction emulation.
+ * support instruction emulation. Ditto for flushing by ASID, as SEV
+ * guests are bound to a single ASID, i.e. KVM can't rotate to a new
+ * ASID to effect a TLB flush.
*/
if (!boot_cpu_has(X86_FEATURE_SEV) ||
- WARN_ON_ONCE(!boot_cpu_has(X86_FEATURE_DECODEASSISTS)))
+ WARN_ON_ONCE(!boot_cpu_has(X86_FEATURE_DECODEASSISTS)) ||
+ WARN_ON_ONCE(!boot_cpu_has(X86_FEATURE_FLUSHBYASID)))
goto out;
/* Retrieve SEV CPUID information */
@@ -2234,8 +2244,10 @@ 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? */
@@ -2266,7 +2278,9 @@ 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",
@@ -2314,7 +2328,7 @@ 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
@@ -2632,7 +2646,7 @@ 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;