KVM: SVM: Allocate SEV command structures on local stack
authorSean Christopherson <seanjc@google.com>
Tue, 6 Apr 2021 22:49:52 +0000 (15:49 -0700)
committerPaolo Bonzini <pbonzini@redhat.com>
Wed, 21 Apr 2021 16:20:07 +0000 (12:20 -0400)
Use the local stack to "allocate" the structures used to communicate with
the PSP.  The largest struct used by KVM, sev_data_launch_secret, clocks
in at 52 bytes, well within the realm of reasonable stack usage.  The
smallest structs are a mere 4 bytes, i.e. the pointer for the allocation
is larger than the allocation itself.

Now that the PSP driver plays nice with vmalloc pointers, putting the
data on a virtually mapped stack (CONFIG_VMAP_STACK=y) will not cause
explosions.

Cc: Brijesh Singh <brijesh.singh@amd.com>
Cc: Tom Lendacky <thomas.lendacky@amd.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
Message-Id: <20210406224952.4177376-9-seanjc@google.com>
Reviewed-by: Brijesh Singh <brijesh.singh@amd.com>
Acked-by: Tom Lendacky <thomas.lendacky@amd.com>
[Apply same treatment to PSP migration commands. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
arch/x86/kvm/svm/sev.c

index 3f766da..b4e471b 100644 (file)
@@ -151,35 +151,22 @@ static void sev_asid_free(int asid)
 
 static void sev_unbind_asid(struct kvm *kvm, unsigned int handle)
 {
-       struct sev_data_decommission *decommission;
-       struct sev_data_deactivate *data;
+       struct sev_data_decommission decommission;
+       struct sev_data_deactivate deactivate;
 
        if (!handle)
                return;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               return;
-
-       /* deactivate handle */
-       data->handle = handle;
+       deactivate.handle = handle;
 
        /* Guard DEACTIVATE against WBINVD/DF_FLUSH used in ASID recycling */
        down_read(&sev_deactivate_lock);
-       sev_guest_deactivate(data, NULL);
+       sev_guest_deactivate(&deactivate, NULL);
        up_read(&sev_deactivate_lock);
 
-       kfree(data);
-
-       decommission = kzalloc(sizeof(*decommission), GFP_KERNEL);
-       if (!decommission)
-               return;
-
        /* decommission handle */
-       decommission->handle = handle;
-       sev_guest_decommission(decommission, NULL);
-
-       kfree(decommission);
+       decommission.handle = handle;
+       sev_guest_decommission(&decommission, NULL);
 }
 
 static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
@@ -217,19 +204,14 @@ e_free:
 
 static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
 {
-       struct sev_data_activate *data;
+       struct sev_data_activate activate;
        int asid = sev_get_asid(kvm);
        int ret;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
-
        /* activate ASID on the given handle */
-       data->handle = handle;
-       data->asid   = asid;
-       ret = sev_guest_activate(data, error);
-       kfree(data);
+       activate.handle = handle;
+       activate.asid   = asid;
+       ret = sev_guest_activate(&activate, error);
 
        return ret;
 }
@@ -259,7 +241,7 @@ static int sev_issue_cmd(struct kvm *kvm, int id, void *data, int *error)
 static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_launch_start *start;
+       struct sev_data_launch_start start;
        struct kvm_sev_launch_start params;
        void *dh_blob, *session_blob;
        int *error = &argp->error;
@@ -271,20 +253,16 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
        if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
                return -EFAULT;
 
-       start = kzalloc(sizeof(*start), GFP_KERNEL_ACCOUNT);
-       if (!start)
-               return -ENOMEM;
+       memset(&start, 0, sizeof(start));
 
        dh_blob = NULL;
        if (params.dh_uaddr) {
                dh_blob = psp_copy_user_blob(params.dh_uaddr, params.dh_len);
-               if (IS_ERR(dh_blob)) {
-                       ret = PTR_ERR(dh_blob);
-                       goto e_free;
-               }
+               if (IS_ERR(dh_blob))
+                       return PTR_ERR(dh_blob);
 
-               start->dh_cert_address = __sme_set(__pa(dh_blob));
-               start->dh_cert_len = params.dh_len;
+               start.dh_cert_address = __sme_set(__pa(dh_blob));
+               start.dh_cert_len = params.dh_len;
        }
 
        session_blob = NULL;
@@ -295,40 +273,38 @@ static int sev_launch_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
                        goto e_free_dh;
                }
 
-               start->session_address = __sme_set(__pa(session_blob));
-               start->session_len = params.session_len;
+               start.session_address = __sme_set(__pa(session_blob));
+               start.session_len = params.session_len;
        }
 
-       start->handle = params.handle;
-       start->policy = params.policy;
+       start.handle = params.handle;
+       start.policy = params.policy;
 
        /* create memory encryption context */
-       ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_LAUNCH_START, start, error);
+       ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_LAUNCH_START, &start, error);
        if (ret)
                goto e_free_session;
 
        /* Bind ASID to this guest */
-       ret = sev_bind_asid(kvm, start->handle, error);
+       ret = sev_bind_asid(kvm, start.handle, error);
        if (ret)
                goto e_free_session;
 
        /* return handle to userspace */
-       params.handle = start->handle;
+       params.handle = start.handle;
        if (copy_to_user((void __user *)(uintptr_t)argp->data, &params, sizeof(params))) {
-               sev_unbind_asid(kvm, start->handle);
+               sev_unbind_asid(kvm, start.handle);
                ret = -EFAULT;
                goto e_free_session;
        }
 
-       sev->handle = start->handle;
+       sev->handle = start.handle;
        sev->fd = argp->sev_fd;
 
 e_free_session:
        kfree(session_blob);
 e_free_dh:
        kfree(dh_blob);
-e_free:
-       kfree(start);
        return ret;
 }
 
@@ -447,7 +423,7 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
        unsigned long vaddr, vaddr_end, next_vaddr, npages, pages, size, i;
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
        struct kvm_sev_launch_update_data params;
-       struct sev_data_launch_update_data *data;
+       struct sev_data_launch_update_data data;
        struct page **inpages;
        int ret;
 
@@ -457,20 +433,14 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
        if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
                return -EFAULT;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
-
        vaddr = params.uaddr;
        size = params.len;
        vaddr_end = vaddr + size;
 
        /* Lock the user memory. */
        inpages = sev_pin_memory(kvm, vaddr, size, &npages, 1);
-       if (IS_ERR(inpages)) {
-               ret = PTR_ERR(inpages);
-               goto e_free;
-       }
+       if (IS_ERR(inpages))
+               return PTR_ERR(inpages);
 
        /*
         * Flush (on non-coherent CPUs) before LAUNCH_UPDATE encrypts pages in
@@ -478,6 +448,9 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
         */
        sev_clflush_pages(inpages, npages);
 
+       data.reserved = 0;
+       data.handle = sev->handle;
+
        for (i = 0; vaddr < vaddr_end; vaddr = next_vaddr, i += pages) {
                int offset, len;
 
@@ -492,10 +465,9 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
                len = min_t(size_t, ((pages * PAGE_SIZE) - offset), size);
 
-               data->handle = sev->handle;
-               data->len = len;
-               data->address = __sme_page_pa(inpages[i]) + offset;
-               ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_DATA, data, &argp->error);
+               data.len = len;
+               data.address = __sme_page_pa(inpages[i]) + offset;
+               ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_DATA, &data, &argp->error);
                if (ret)
                        goto e_unpin;
 
@@ -511,8 +483,6 @@ e_unpin:
        }
        /* unlock the user pages */
        sev_unpin_memory(kvm, inpages, npages);
-e_free:
-       kfree(data);
        return ret;
 }
 
@@ -564,16 +534,14 @@ static int sev_es_sync_vmsa(struct vcpu_svm *svm)
 static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_launch_update_vmsa *vmsa;
+       struct sev_data_launch_update_vmsa vmsa;
        struct kvm_vcpu *vcpu;
        int i, ret;
 
        if (!sev_es_guest(kvm))
                return -ENOTTY;
 
-       vmsa = kzalloc(sizeof(*vmsa), GFP_KERNEL);
-       if (!vmsa)
-               return -ENOMEM;
+       vmsa.reserved = 0;
 
        kvm_for_each_vcpu(i, vcpu, kvm) {
                struct vcpu_svm *svm = to_svm(vcpu);
@@ -581,7 +549,7 @@ static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
                /* Perform some pre-encryption checks against the VMSA */
                ret = sev_es_sync_vmsa(svm);
                if (ret)
-                       goto e_free;
+                       return ret;
 
                /*
                 * The LAUNCH_UPDATE_VMSA command will perform in-place
@@ -591,27 +559,25 @@ static int sev_launch_update_vmsa(struct kvm *kvm, struct kvm_sev_cmd *argp)
                 */
                clflush_cache_range(svm->vmsa, PAGE_SIZE);
 
-               vmsa->handle = sev->handle;
-               vmsa->address = __sme_pa(svm->vmsa);
-               vmsa->len = PAGE_SIZE;
-               ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_VMSA, vmsa,
+               vmsa.handle = sev->handle;
+               vmsa.address = __sme_pa(svm->vmsa);
+               vmsa.len = PAGE_SIZE;
+               ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_VMSA, &vmsa,
                                    &argp->error);
                if (ret)
-                       goto e_free;
+                       return ret;
 
                svm->vcpu.arch.guest_state_protected = true;
        }
 
-e_free:
-       kfree(vmsa);
-       return ret;
+       return 0;
 }
 
 static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        void __user *measure = (void __user *)(uintptr_t)argp->data;
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_launch_measure *data;
+       struct sev_data_launch_measure data;
        struct kvm_sev_launch_measure params;
        void __user *p = NULL;
        void *blob = NULL;
@@ -623,9 +589,7 @@ static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
        if (copy_from_user(&params, measure, sizeof(params)))
                return -EFAULT;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
+       memset(&data, 0, sizeof(data));
 
        /* User wants to query the blob length */
        if (!params.len)
@@ -633,23 +597,20 @@ static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
        p = (void __user *)(uintptr_t)params.uaddr;
        if (p) {
-               if (params.len > SEV_FW_BLOB_MAX_SIZE) {
-                       ret = -EINVAL;
-                       goto e_free;
-               }
+               if (params.len > SEV_FW_BLOB_MAX_SIZE)
+                       return -EINVAL;
 
-               ret = -ENOMEM;
                blob = kmalloc(params.len, GFP_KERNEL_ACCOUNT);
                if (!blob)
-                       goto e_free;
+                       return -ENOMEM;
 
-               data->address = __psp_pa(blob);
-               data->len = params.len;
+               data.address = __psp_pa(blob);
+               data.len = params.len;
        }
 
 cmd:
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_MEASURE, data, &argp->error);
+       data.handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_MEASURE, &data, &argp->error);
 
        /*
         * If we query the session length, FW responded with expected data.
@@ -666,63 +627,50 @@ cmd:
        }
 
 done:
-       params.len = data->len;
+       params.len = data.len;
        if (copy_to_user(measure, &params, sizeof(params)))
                ret = -EFAULT;
 e_free_blob:
        kfree(blob);
-e_free:
-       kfree(data);
        return ret;
 }
 
 static int sev_launch_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_launch_finish *data;
-       int ret;
+       struct sev_data_launch_finish data;
 
        if (!sev_guest(kvm))
                return -ENOTTY;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
-
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_FINISH, data, &argp->error);
-
-       kfree(data);
-       return ret;
+       data.handle = sev->handle;
+       return sev_issue_cmd(kvm, SEV_CMD_LAUNCH_FINISH, &data, &argp->error);
 }
 
 static int sev_guest_status(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
        struct kvm_sev_guest_status params;
-       struct sev_data_guest_status *data;
+       struct sev_data_guest_status data;
        int ret;
 
        if (!sev_guest(kvm))
                return -ENOTTY;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
+       memset(&data, 0, sizeof(data));
 
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_GUEST_STATUS, data, &argp->error);
+       data.handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_GUEST_STATUS, &data, &argp->error);
        if (ret)
-               goto e_free;
+               return ret;
 
-       params.policy = data->policy;
-       params.state = data->state;
-       params.handle = data->handle;
+       params.policy = data.policy;
+       params.state = data.state;
+       params.handle = data.handle;
 
        if (copy_to_user((void __user *)(uintptr_t)argp->data, &params, sizeof(params)))
                ret = -EFAULT;
-e_free:
-       kfree(data);
+
        return ret;
 }
 
@@ -731,23 +679,17 @@ static int __sev_issue_dbg_cmd(struct kvm *kvm, unsigned long src,
                               int *error, bool enc)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_dbg *data;
-       int ret;
+       struct sev_data_dbg data;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
-
-       data->handle = sev->handle;
-       data->dst_addr = dst;
-       data->src_addr = src;
-       data->len = size;
+       data.reserved = 0;
+       data.handle = sev->handle;
+       data.dst_addr = dst;
+       data.src_addr = src;
+       data.len = size;
 
-       ret = sev_issue_cmd(kvm,
-                           enc ? SEV_CMD_DBG_ENCRYPT : SEV_CMD_DBG_DECRYPT,
-                           data, error);
-       kfree(data);
-       return ret;
+       return sev_issue_cmd(kvm,
+                            enc ? SEV_CMD_DBG_ENCRYPT : SEV_CMD_DBG_DECRYPT,
+                            &data, error);
 }
 
 static int __sev_dbg_decrypt(struct kvm *kvm, unsigned long src_paddr,
@@ -967,7 +909,7 @@ err:
 static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_launch_secret *data;
+       struct sev_data_launch_secret data;
        struct kvm_sev_launch_secret params;
        struct page **pages;
        void *blob, *hdr;
@@ -999,41 +941,36 @@ static int sev_launch_secret(struct kvm *kvm, struct kvm_sev_cmd *argp)
                goto e_unpin_memory;
        }
 
-       ret = -ENOMEM;
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               goto e_unpin_memory;
+       memset(&data, 0, sizeof(data));
 
        offset = params.guest_uaddr & (PAGE_SIZE - 1);
-       data->guest_address = __sme_page_pa(pages[0]) + offset;
-       data->guest_len = params.guest_len;
+       data.guest_address = __sme_page_pa(pages[0]) + offset;
+       data.guest_len = params.guest_len;
 
        blob = psp_copy_user_blob(params.trans_uaddr, params.trans_len);
        if (IS_ERR(blob)) {
                ret = PTR_ERR(blob);
-               goto e_free;
+               goto e_unpin_memory;
        }
 
-       data->trans_address = __psp_pa(blob);
-       data->trans_len = params.trans_len;
+       data.trans_address = __psp_pa(blob);
+       data.trans_len = params.trans_len;
 
        hdr = psp_copy_user_blob(params.hdr_uaddr, params.hdr_len);
        if (IS_ERR(hdr)) {
                ret = PTR_ERR(hdr);
                goto e_free_blob;
        }
-       data->hdr_address = __psp_pa(hdr);
-       data->hdr_len = params.hdr_len;
+       data.hdr_address = __psp_pa(hdr);
+       data.hdr_len = params.hdr_len;
 
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_SECRET, data, &argp->error);
+       data.handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_LAUNCH_UPDATE_SECRET, &data, &argp->error);
 
        kfree(hdr);
 
 e_free_blob:
        kfree(blob);
-e_free:
-       kfree(data);
 e_unpin_memory:
        /* content of memory is updated, mark pages dirty */
        for (i = 0; i < n; i++) {
@@ -1048,7 +985,7 @@ static int sev_get_attestation_report(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        void __user *report = (void __user *)(uintptr_t)argp->data;
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_attestation_report *data;
+       struct sev_data_attestation_report data;
        struct kvm_sev_attestation_report params;
        void __user *p;
        void *blob = NULL;
@@ -1060,9 +997,7 @@ static int sev_get_attestation_report(struct kvm *kvm, struct kvm_sev_cmd *argp)
        if (copy_from_user(&params, (void __user *)(uintptr_t)argp->data, sizeof(params)))
                return -EFAULT;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
+       memset(&data, 0, sizeof(data));
 
        /* User wants to query the blob length */
        if (!params.len)
@@ -1070,23 +1005,20 @@ static int sev_get_attestation_report(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
        p = (void __user *)(uintptr_t)params.uaddr;
        if (p) {
-               if (params.len > SEV_FW_BLOB_MAX_SIZE) {
-                       ret = -EINVAL;
-                       goto e_free;
-               }
+               if (params.len > SEV_FW_BLOB_MAX_SIZE)
+                       return -EINVAL;
 
-               ret = -ENOMEM;
                blob = kmalloc(params.len, GFP_KERNEL_ACCOUNT);
                if (!blob)
-                       goto e_free;
+                       return -ENOMEM;
 
-               data->address = __psp_pa(blob);
-               data->len = params.len;
-               memcpy(data->mnonce, params.mnonce, sizeof(params.mnonce));
+               data.address = __psp_pa(blob);
+               data.len = params.len;
+               memcpy(data.mnonce, params.mnonce, sizeof(params.mnonce));
        }
 cmd:
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_ATTESTATION_REPORT, data, &argp->error);
+       data.handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_ATTESTATION_REPORT, &data, &argp->error);
        /*
         * If we query the session length, FW responded with expected data.
         */
@@ -1102,13 +1034,11 @@ cmd:
        }
 
 done:
-       params.len = data->len;
+       params.len = data.len;
        if (copy_to_user(report, &params, sizeof(params)))
                ret = -EFAULT;
 e_free_blob:
        kfree(blob);
-e_free:
-       kfree(data);
        return ret;
 }
 
@@ -1118,32 +1048,26 @@ __sev_send_start_query_session_length(struct kvm *kvm, struct kvm_sev_cmd *argp,
                                      struct kvm_sev_send_start *params)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_send_start *data;
+       struct sev_data_send_start data;
        int ret;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (data == NULL)
-               return -ENOMEM;
-
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+       data.handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, &data, &argp->error);
        if (ret < 0)
-               goto out;
+               return ret;
 
-       params->session_len = data->session_len;
+       params->session_len = data.session_len;
        if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
                                sizeof(struct kvm_sev_send_start)))
                ret = -EFAULT;
 
-out:
-       kfree(data);
        return ret;
 }
 
 static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_send_start *data;
+       struct sev_data_send_start data;
        struct kvm_sev_send_start params;
        void *amd_certs, *session_data;
        void *pdh_cert, *plat_certs;
@@ -1193,39 +1117,32 @@ static int sev_send_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
                goto e_free_plat_cert;
        }
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (data == NULL) {
-               ret = -ENOMEM;
-               goto e_free_amd_cert;
-       }
-
        /* populate the FW SEND_START field with system physical address */
-       data->pdh_cert_address = __psp_pa(pdh_cert);
-       data->pdh_cert_len = params.pdh_cert_len;
-       data->plat_certs_address = __psp_pa(plat_certs);
-       data->plat_certs_len = params.plat_certs_len;
-       data->amd_certs_address = __psp_pa(amd_certs);
-       data->amd_certs_len = params.amd_certs_len;
-       data->session_address = __psp_pa(session_data);
-       data->session_len = params.session_len;
-       data->handle = sev->handle;
-
-       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, data, &argp->error);
+       memset(&data, 0, sizeof(data));
+       data.pdh_cert_address = __psp_pa(pdh_cert);
+       data.pdh_cert_len = params.pdh_cert_len;
+       data.plat_certs_address = __psp_pa(plat_certs);
+       data.plat_certs_len = params.plat_certs_len;
+       data.amd_certs_address = __psp_pa(amd_certs);
+       data.amd_certs_len = params.amd_certs_len;
+       data.session_address = __psp_pa(session_data);
+       data.session_len = params.session_len;
+       data.handle = sev->handle;
+
+       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_START, &data, &argp->error);
 
        if (!ret && copy_to_user((void __user *)(uintptr_t)params.session_uaddr,
                        session_data, params.session_len)) {
                ret = -EFAULT;
-               goto e_free;
+               goto e_free_amd_cert;
        }
 
-       params.policy = data->policy;
-       params.session_len = data->session_len;
+       params.policy = data.policy;
+       params.session_len = data.session_len;
        if (copy_to_user((void __user *)(uintptr_t)argp->data, &params,
                                sizeof(struct kvm_sev_send_start)))
                ret = -EFAULT;
 
-e_free:
-       kfree(data);
 e_free_amd_cert:
        kfree(amd_certs);
 e_free_plat_cert:
@@ -1243,34 +1160,28 @@ __sev_send_update_data_query_lengths(struct kvm *kvm, struct kvm_sev_cmd *argp,
                                     struct kvm_sev_send_update_data *params)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_send_update_data *data;
+       struct sev_data_send_update_data data;
        int ret;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
-       if (!data)
-               return -ENOMEM;
-
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_UPDATE_DATA, data, &argp->error);
+       data.handle = sev->handle;
+       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_UPDATE_DATA, &data, &argp->error);
        if (ret < 0)
-               goto out;
+               return ret;
 
-       params->hdr_len = data->hdr_len;
-       params->trans_len = data->trans_len;
+       params->hdr_len = data.hdr_len;
+       params->trans_len = data.trans_len;
 
        if (copy_to_user((void __user *)(uintptr_t)argp->data, params,
                         sizeof(struct kvm_sev_send_update_data)))
                ret = -EFAULT;
 
-out:
-       kfree(data);
        return ret;
 }
 
 static int sev_send_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_send_update_data *data;
+       struct sev_data_send_update_data data;
        struct kvm_sev_send_update_data params;
        void *hdr, *trans_data;
        struct page **guest_page;
@@ -1313,40 +1224,34 @@ static int sev_send_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
        if (!trans_data)
                goto e_free_hdr;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               goto e_free_trans_data;
-
-       data->hdr_address = __psp_pa(hdr);
-       data->hdr_len = params.hdr_len;
-       data->trans_address = __psp_pa(trans_data);
-       data->trans_len = params.trans_len;
+       memset(&data, 0, sizeof(data));
+       data.hdr_address = __psp_pa(hdr);
+       data.hdr_len = params.hdr_len;
+       data.trans_address = __psp_pa(trans_data);
+       data.trans_len = params.trans_len;
 
        /* The SEND_UPDATE_DATA command requires C-bit to be always set. */
-       data->guest_address = (page_to_pfn(guest_page[0]) << PAGE_SHIFT) +
-                               offset;
-       data->guest_address |= sev_me_mask;
-       data->guest_len = params.guest_len;
-       data->handle = sev->handle;
+       data.guest_address = (page_to_pfn(guest_page[0]) << PAGE_SHIFT) + offset;
+       data.guest_address |= sev_me_mask;
+       data.guest_len = params.guest_len;
+       data.handle = sev->handle;
 
-       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_UPDATE_DATA, data, &argp->error);
+       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_UPDATE_DATA, &data, &argp->error);
 
        if (ret)
-               goto e_free;
+               goto e_free_trans_data;
 
        /* copy transport buffer to user space */
        if (copy_to_user((void __user *)(uintptr_t)params.trans_uaddr,
                         trans_data, params.trans_len)) {
                ret = -EFAULT;
-               goto e_free;
+               goto e_free_trans_data;
        }
 
        /* Copy packet header to userspace. */
        ret = copy_to_user((void __user *)(uintptr_t)params.hdr_uaddr, hdr,
                                params.hdr_len);
 
-e_free:
-       kfree(data);
 e_free_trans_data:
        kfree(trans_data);
 e_free_hdr:
@@ -1360,47 +1265,31 @@ e_unpin:
 static int sev_send_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_send_finish *data;
-       int ret;
+       struct sev_data_send_finish data;
 
        if (!sev_guest(kvm))
                return -ENOTTY;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               return -ENOMEM;
-
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_FINISH, data, &argp->error);
-
-       kfree(data);
-       return ret;
+       data.handle = sev->handle;
+       return sev_issue_cmd(kvm, SEV_CMD_SEND_FINISH, &data, &argp->error);
 }
 
 static int sev_send_cancel(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_send_cancel *data;
-       int ret;
+       struct sev_data_send_cancel data;
 
        if (!sev_guest(kvm))
                return -ENOTTY;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               return -ENOMEM;
-
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_SEND_CANCEL, data, &argp->error);
-
-       kfree(data);
-       return ret;
+       data.handle = sev->handle;
+       return sev_issue_cmd(kvm, SEV_CMD_SEND_CANCEL, &data, &argp->error);
 }
 
 static int sev_receive_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_receive_start *start;
+       struct sev_data_receive_start start;
        struct kvm_sev_receive_start params;
        int *error = &argp->error;
        void *session_data;
@@ -1431,42 +1320,36 @@ static int sev_receive_start(struct kvm *kvm, struct kvm_sev_cmd *argp)
                goto e_free_pdh;
        }
 
-       ret = -ENOMEM;
-       start = kzalloc(sizeof(*start), GFP_KERNEL);
-       if (!start)
-               goto e_free_session;
-
-       start->handle = params.handle;
-       start->policy = params.policy;
-       start->pdh_cert_address = __psp_pa(pdh_data);
-       start->pdh_cert_len = params.pdh_len;
-       start->session_address = __psp_pa(session_data);
-       start->session_len = params.session_len;
+       memset(&start, 0, sizeof(start));
+       start.handle = params.handle;
+       start.policy = params.policy;
+       start.pdh_cert_address = __psp_pa(pdh_data);
+       start.pdh_cert_len = params.pdh_len;
+       start.session_address = __psp_pa(session_data);
+       start.session_len = params.session_len;
 
        /* create memory encryption context */
-       ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_RECEIVE_START, start,
+       ret = __sev_issue_cmd(argp->sev_fd, SEV_CMD_RECEIVE_START, &start,
                                error);
        if (ret)
-               goto e_free;
+               goto e_free_session;
 
        /* Bind ASID to this guest */
-       ret = sev_bind_asid(kvm, start->handle, error);
+       ret = sev_bind_asid(kvm, start.handle, error);
        if (ret)
-               goto e_free;
+               goto e_free_session;
 
-       params.handle = start->handle;
+       params.handle = start.handle;
        if (copy_to_user((void __user *)(uintptr_t)argp->data,
                         &params, sizeof(struct kvm_sev_receive_start))) {
                ret = -EFAULT;
-               sev_unbind_asid(kvm, start->handle);
-               goto e_free;
+               sev_unbind_asid(kvm, start.handle);
+               goto e_free_session;
        }
 
-       sev->handle = start->handle;
+       sev->handle = start.handle;
        sev->fd = argp->sev_fd;
 
-e_free:
-       kfree(start);
 e_free_session:
        kfree(session_data);
 e_free_pdh:
@@ -1479,7 +1362,7 @@ static int sev_receive_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
        struct kvm_sev_receive_update_data params;
-       struct sev_data_receive_update_data *data;
+       struct sev_data_receive_update_data data;
        void *hdr = NULL, *trans = NULL;
        struct page **guest_page;
        unsigned long n;
@@ -1512,37 +1395,30 @@ static int sev_receive_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
                goto e_free_hdr;
        }
 
-       ret = -ENOMEM;
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               goto e_free_trans;
-
-       data->hdr_address = __psp_pa(hdr);
-       data->hdr_len = params.hdr_len;
-       data->trans_address = __psp_pa(trans);
-       data->trans_len = params.trans_len;
+       memset(&data, 0, sizeof(data));
+       data.hdr_address = __psp_pa(hdr);
+       data.hdr_len = params.hdr_len;
+       data.trans_address = __psp_pa(trans);
+       data.trans_len = params.trans_len;
 
        /* Pin guest memory */
        ret = -EFAULT;
        guest_page = sev_pin_memory(kvm, params.guest_uaddr & PAGE_MASK,
                                    PAGE_SIZE, &n, 0);
        if (!guest_page)
-               goto e_free;
+               goto e_free_trans;
 
        /* The RECEIVE_UPDATE_DATA command requires C-bit to be always set. */
-       data->guest_address = (page_to_pfn(guest_page[0]) << PAGE_SHIFT) +
-                               offset;
-       data->guest_address |= sev_me_mask;
-       data->guest_len = params.guest_len;
-       data->handle = sev->handle;
+       data.guest_address = (page_to_pfn(guest_page[0]) << PAGE_SHIFT) + offset;
+       data.guest_address |= sev_me_mask;
+       data.guest_len = params.guest_len;
+       data.handle = sev->handle;
 
-       ret = sev_issue_cmd(kvm, SEV_CMD_RECEIVE_UPDATE_DATA, data,
+       ret = sev_issue_cmd(kvm, SEV_CMD_RECEIVE_UPDATE_DATA, &data,
                                &argp->error);
 
        sev_unpin_memory(kvm, guest_page, n);
 
-e_free:
-       kfree(data);
 e_free_trans:
        kfree(trans);
 e_free_hdr:
@@ -1554,21 +1430,13 @@ e_free_hdr:
 static int sev_receive_finish(struct kvm *kvm, struct kvm_sev_cmd *argp)
 {
        struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
-       struct sev_data_receive_finish *data;
-       int ret;
+       struct sev_data_receive_finish data;
 
        if (!sev_guest(kvm))
                return -ENOTTY;
 
-       data = kzalloc(sizeof(*data), GFP_KERNEL);
-       if (!data)
-               return -ENOMEM;
-
-       data->handle = sev->handle;
-       ret = sev_issue_cmd(kvm, SEV_CMD_RECEIVE_FINISH, data, &argp->error);
-
-       kfree(data);
-       return ret;
+       data.handle = sev->handle;
+       return sev_issue_cmd(kvm, SEV_CMD_RECEIVE_FINISH, &data, &argp->error);
 }
 
 int svm_mem_enc_op(struct kvm *kvm, void __user *argp)