KVM: SVM: Remove unneeded WBINVD and DF_FLUSH when starting SEV guests

Performing a WBINVD and DF_FLUSH are expensive operations. The SEV support
currently performs this WBINVD/DF_FLUSH combination when an SEV guest is
terminated, so there is no need for it to be done before LAUNCH.

However, when the SEV firmware transitions the platform from UNINIT state
to INIT state, all ASIDs will be marked invalid across all threads.
Therefore, as part of transitioning the platform to INIT state, perform a
WBINVD/DF_FLUSH after a successful INIT in the PSP/SEV device driver.
Since the PSP/SEV device driver is x86 only, it can reference and use the
WBINVD related functions directly.

Cc: Gary Hook <gary.hook@amd.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: "David S. Miller" <davem@davemloft.net>
Tested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

diff --git a/arch/x86/kvm/svm.c b/arch/x86/kvm/svm.c
index 1d217680cf83dd2baa8b00de202d60cfdc49ea63..389dfd7594eb82d219f16183f831c19b40c7a221 100644 (file)
--- a/arch/x86/kvm/svm.c
+++ b/arch/x86/kvm/svm.c
@@ -6329,21 +6329,6 @@ static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
        int asid = sev_get_asid(kvm);
        int ret;
 
-       /*
-        * Guard against a DEACTIVATE command before the DF_FLUSH command
-        * has completed.
-        */
-       mutex_lock(&sev_deactivate_lock);
-
-       wbinvd_on_all_cpus();
-
-       ret = sev_guest_df_flush(error);
-
-       mutex_unlock(&sev_deactivate_lock);
-
-       if (ret)
-               return ret;
-
        data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
        if (!data)
                return -ENOMEM;

diff --git a/drivers/crypto/ccp/psp-dev.c b/drivers/crypto/ccp/psp-dev.c
index 6b17d179ef8a0574bcfb6c77a0119c6b765f6177..39fdd0641637f590cb6f328953ffbb1eaf810f17 100644 (file)
--- a/drivers/crypto/ccp/psp-dev.c
+++ b/drivers/crypto/ccp/psp-dev.c
@@ -21,6 +21,8 @@
 #include <linux/ccp.h>
 #include <linux/firmware.h>
 
+#include <asm/smp.h>
+
 #include "sp-dev.h"
 #include "psp-dev.h"
 
@@ -235,6 +237,13 @@ static int __sev_platform_init_locked(int *error)
                return rc;
 
        psp->sev_state = SEV_STATE_INIT;
+
+       /* Prepare for first SEV guest launch after INIT */
+       wbinvd_on_all_cpus();
+       rc = __sev_do_cmd_locked(SEV_CMD_DF_FLUSH, NULL, error);
+       if (rc)
+               return rc;
+
        dev_dbg(psp->dev, "SEV firmware initialized\n");
 
        return rc;