In KVM SEV code, sev_unbind_asid and sev_guest_df_flush needs to be
serialized because DEACTIVATE command in PSP may clear the WBINVD indicator
and cause DF_FLUSH to fail.
This is a PSP level detail that is not necessary to expose to KVM. So put
both functions as well as the RWSEM into the sev-dev.c.
No functional change intended.
Cc: Alper Gun <alpergun@xxxxxxxxxx>
Cc: Borislav Petkov <bp@xxxxxxxxx>
Cc: Brijesh Singh <brijesh.singh@xxxxxxx>
Cc: David Rienjes <rientjes@xxxxxxxxxx>
Cc: Marc Orr <marcorr@xxxxxxxxxx>
Cc: John Allen <john.allen@xxxxxxx>
Cc: Peter Gonda <pgonda@xxxxxxxxxx>
Cc: Sean Christopherson <seanjc@xxxxxxxxxx>
Cc: Tom Lendacky <thomas.lendacky@xxxxxxx>
Cc: Vipin Sharma <vipinsh@xxxxxxxxxx>
Acked-by: Brijesh Singh <brijesh.singh@xxxxxxx>
Signed-off-by: Mingwei Zhang <mizhang@xxxxxxxxxx>
---
arch/x86/kvm/svm/sev.c | 35 +++-------------------------------
drivers/crypto/ccp/sev-dev.c | 37 +++++++++++++++++++++++++++++++++++-
include/linux/psp-sev.h | 19 +++++++++++++++++-
3 files changed, 57 insertions(+), 34 deletions(-)
diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 157962aa4aff..ab5f14adc591 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -57,7 +57,6 @@ module_param_named(sev_es, sev_es_enabled, bool, 0444);
#endif /* CONFIG_KVM_AMD_SEV */
static u8 sev_enc_bit;
-static DECLARE_RWSEM(sev_deactivate_lock);
static DEFINE_MUTEX(sev_bitmap_lock);
unsigned int max_sev_asid;
static unsigned int min_sev_asid;
@@ -84,20 +83,9 @@ static int sev_flush_asids(int min_asid, int max_asid)
if (asid > max_asid)
return -EBUSY;
- /*
- * DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail,
- * so it must be guarded.
- */
- down_write(&sev_deactivate_lock);
-
- wbinvd_on_all_cpus();
ret = sev_guest_df_flush(&error);
-
- up_write(&sev_deactivate_lock);
-
if (ret)
pr_err("SEV: DF_FLUSH failed, ret=%d, error=%#x\n", ret, error);
-
return ret;
}
@@ -198,23 +186,6 @@ static void sev_asid_free(struct kvm_sev_info *sev)
sev->misc_cg = NULL;
}
-static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
-{
- struct sev_data_deactivate deactivate;
-
- if (!handle)
- return;
-
- deactivate.handle = handle;
-
- /* Guard DEACTIVATE against WBINVD/DF_FLUSH used in ASID recycling */
- down_read(&sev_deactivate_lock);
- sev_guest_deactivate(&deactivate, NULL);
- up_read(&sev_deactivate_lock);
-
- sev_guest_decommission(handle, NULL);
-}
-
static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
@@ -329,7 +300,7 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
/* return handle to userspace */
params.handle = start.handle;
if (copy_to_user((void __user *)(uintptr_t)argp->data, ¶ms, sizeof(params))) {
- sev_unbind_asid(kvm, start.handle);
+ sev_guest_unbind_asid(start.handle);
ret = -EFAULT;
goto e_free_session;
}
@@ -1377,7 +1348,7 @@ static int sev_receive_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
if (copy_to_user((void __user *)(uintptr_t)argp->data,
¶ms, sizeof(struct kvm_sev_receive_start))) {
ret = -EFAULT;
- sev_unbind_asid(kvm, start.handle);
+ sev_guest_unbind_asid(start.handle);
goto e_free_session;
}
@@ -1788,7 +1759,7 @@ void sev_vm_destroy(struct kvm *kvm)
mutex_unlock(&kvm->lock);
- sev_unbind_asid(kvm, sev->handle);
+ sev_guest_unbind_asid(sev->handle);
sev_asid_free(sev);
}
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index 325e79360d9e..e318a1a222f9 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -33,6 +33,7 @@
#define SEV_FW_NAME_SIZE 64
static DEFINE_MUTEX(sev_cmd_mutex);
+static DECLARE_RWSEM(sev_deactivate_lock);
static struct sev_misc_dev *misc_dev;
static int psp_cmd_timeout = 100;
@@ -932,10 +933,44 @@ EXPORT_SYMBOL_GPL(sev_guest_decommission);
int sev_guest_df_flush(int *error)
{
- return sev_do_cmd(SEV_CMD_DF_FLUSH, NULL, error);
+ int ret;
+ /*
+ * DEACTIVATE will clear the WBINVD indicator causing DF_FLUSH to fail,
+ * so it must be guarded.
+ */
+ down_write(&sev_deactivate_lock);
+
+ wbinvd_on_all_cpus();
+
+ ret = sev_do_cmd(SEV_CMD_DF_FLUSH, NULL, error);
+
+ up_write(&sev_deactivate_lock);
+
+ return ret;
}
EXPORT_SYMBOL_GPL(sev_guest_df_flush);
+int sev_guest_unbind_asid(unsigned int handle)
+{
+ struct sev_data_deactivate deactivate;
+ int ret;
+
+ if (!handle)
+ return -EINVAL;
+
+ deactivate.handle = handle;
+
+ /* Guard DEACTIVATE against WBINVD/DF_FLUSH used in ASID recycling */
+ down_read(&sev_deactivate_lock);
+ ret = sev_guest_deactivate(&deactivate, NULL);
+ up_read(&sev_deactivate_lock);
+
+ sev_guest_decommission(handle, NULL);
+
+ return ret;
+}
+EXPORT_SYMBOL_GPL(sev_guest_unbind_asid);
+
static void sev_exit(struct kref *ref)
{
misc_deregister(&misc_dev->misc);
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index be50446ff3f1..09447bce9665 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -580,6 +580,20 @@ int sev_issue_cmd_external_user(struct file *filep, unsigned int id,
*/
int sev_guest_deactivate(struct sev_data_deactivate *data, int *error);
+/**
+ * sev_guest_unbind_asid - perform SEV DEACTIVATE command with lock held
+ *
+ * @handle: handle of the VM to deactivate
+ *
+ * Returns:
+ * 0 if the sev successfully processed the command
+ * -%ENODEV if the sev device is not available
+ * -%ENOTSUPP if the sev does not support SEV
+ * -%ETIMEDOUT if the sev command timed out
+ * -%EIO if the sev returned a non-zero return code
+ */
+int sev_guest_unbind_asid(unsigned int handle);
+
/**
* sev_guest_activate - perform SEV ACTIVATE command
*
@@ -612,7 +626,7 @@ int sev_guest_activate(struct sev_data_activate *data, int *error);
int sev_guest_bind_asid(int asid, unsigned int handle, int *error);
/**
- * sev_guest_df_flush - perform SEV DF_FLUSH command
+ * sev_guest_df_flush - perform SEV DF_FLUSH command with lock held
*
* @sev_ret: sev command return code
*
@@ -656,6 +670,9 @@ sev_guest_deactivate(struct sev_data_deactivate *data, int *error) { return -ENO
static inline int
sev_guest_decommission(unsigned int handle, int *error) { return -ENODEV; }
+static inline int
+sev_guest_unbind_asid(unsigned int handle) { return -ENODEV; }
+
static inline int
sev_guest_activate(struct sev_data_activate *data, int *error) { return -ENODEV; }
--
2.33.0.rc1.237.g0d66db33f3-goog
