diff mbox series

[v2,8/8] KVM: SVM: Allocate SEV command structures on local stack

Message ID 20210406224952.4177376-9-seanjc@google.com (mailing list archive)
State New
Headers show
Series ccp: KVM: SVM: Use stack for SEV command buffers | expand

Commit Message

Sean Christopherson April 6, 2021, 10:49 p.m. UTC
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>
---
 arch/x86/kvm/svm/sev.c | 262 +++++++++++++++--------------------------
 1 file changed, 96 insertions(+), 166 deletions(-)

Comments

Christophe Leroy April 7, 2021, 5:24 a.m. UTC | #1
Le 07/04/2021 à 00:49, Sean Christopherson a écrit :
> 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>
> ---
>   arch/x86/kvm/svm/sev.c | 262 +++++++++++++++--------------------------
>   1 file changed, 96 insertions(+), 166 deletions(-)
> 
> diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
> index 5457138c7347..316fd39c7aef 100644
> --- a/arch/x86/kvm/svm/sev.c
> +++ b/arch/x86/kvm/svm/sev.c
> @@ -150,35 +150,22 @@ 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)
> @@ -216,19 +203,14 @@ static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
>   
>   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;
>   }
> @@ -258,7 +240,7 @@ 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 sev_data_launch_start start = {0, 0, 0, 0, 0, 0, 0};

>   	struct kvm_sev_launch_start params;
>   	void *dh_blob, *session_blob;
>   	int *error = &argp->error;
> @@ -270,20 +252,16 @@ 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));

Not needed.

>   
>   	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;
> @@ -294,40 +272,38 @@ 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;
>   }
>   
> @@ -446,7 +422,7 @@ 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;
>   
> @@ -456,20 +432,14 @@ 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
> @@ -477,6 +447,9 @@ 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;
>   
> @@ -491,10 +464,9 @@ 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;
>   
> @@ -510,8 +482,6 @@ static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
>   	}
>   	/* unlock the user pages */
>   	sev_unpin_memory(kvm, inpages, npages);
> -e_free:
> -	kfree(data);
>   	return ret;
>   }
>   
> @@ -563,16 +533,14 @@ 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);
> @@ -580,7 +548,7 @@ 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
> @@ -590,27 +558,25 @@ 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 sev_data_launch_measure data = {0, 0, 0, 0};

>   	struct kvm_sev_launch_measure params;
>   	void __user *p = NULL;
>   	void *blob = NULL;
> @@ -622,9 +588,7 @@ 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));

Not needed

>   
>   	/* User wants to query the blob length */
>   	if (!params.len)
> @@ -632,23 +596,20 @@ 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.
> @@ -665,63 +626,50 @@ static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
>   	}
>   
>   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 = {0, 0, 0, 0};
>   	int ret;
>   
>   	if (!sev_guest(kvm))
>   		return -ENOTTY;
>   
> -	data = kzalloc(sizeof(*data), GFP_KERNEL_ACCOUNT);
> -	if (!data)
> -		return -ENOMEM;
> +	memset(&data, 0, sizeof(data));

not needed

>   
> -	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;
>   }
>   
> @@ -730,23 +678,17 @@ 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.reserved = 0;
> +	data.handle = sev->handle;
> +	data.dst_addr = dst;
> +	data.src_addr = src;
> +	data.len = size;
>   
> -	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,
> @@ -966,7 +908,7 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
>   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;
> @@ -998,41 +940,36 @@ 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++) {
> @@ -1047,7 +984,7 @@ 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;
> @@ -1059,9 +996,7 @@ 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)
> @@ -1069,23 +1004,20 @@ 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.
>   	 */
> @@ -1101,13 +1033,11 @@ static int sev_get_attestation_report(struct kvm *kvm, struct kvm_sev_cmd *argp)
>   	}
>   
>   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;
>   }
>   
>
Borislav Petkov April 7, 2021, 10:24 a.m. UTC | #2
First of all, I'd strongly suggest you trim your emails when you reply -
that would be much appreciated.

On Wed, Apr 07, 2021 at 07:24:54AM +0200, Christophe Leroy wrote:
> > @@ -258,7 +240,7 @@ 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 sev_data_launch_start start = {0, 0, 0, 0, 0, 0, 0};

I don't know how this is any better than using memset...

Also, you can do

	... start = { };

which is certainly the only other alternative to memset, AFAIK.

But whatever you do, you need to look at the resulting asm the compiler
generates. So let's do that:

Your version:

# arch/x86/kvm/svm/sev.c:261:   struct sev_data_launch_start _tmp = {0, 0, 0, 0, 0, 0, 0};
        movq    $0, 104(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movq    $0, 112(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movq    $0, 120(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movq    $0, 128(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movl    $0, 136(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]


my version:

# arch/x86/kvm/svm/sev.c:261:   struct sev_data_launch_start _tmp = {};
        movq    $0, 104(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movq    $0, 112(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movq    $0, 120(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movq    $0, 128(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]
        movl    $0, 136(%rsp)   #, MEM[(struct sev_data_launch_start *)_561]


the memset version:

# arch/x86/kvm/svm/sev.c:269: 	memset(&_tmp, 0, sizeof(_tmp));
#NO_APP
	movq	$0, 104(%rsp)	#, MEM <char[1:36]> [(void *)_561]
	movq	$0, 112(%rsp)	#, MEM <char[1:36]> [(void *)_561]
	movq	$0, 120(%rsp)	#, MEM <char[1:36]> [(void *)_561]
	movq	$0, 128(%rsp)	#, MEM <char[1:36]> [(void *)_561]
	movl	$0, 136(%rsp)	#, MEM <char[1:36]> [(void *)_561]

Ok?
Sean Christopherson April 7, 2021, 5:05 p.m. UTC | #3
On Wed, Apr 07, 2021, Borislav Petkov wrote:
> First of all, I'd strongly suggest you trim your emails when you reply -
> that would be much appreciated.
> 
> On Wed, Apr 07, 2021 at 07:24:54AM +0200, Christophe Leroy wrote:
> > > @@ -258,7 +240,7 @@ 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 sev_data_launch_start start = {0, 0, 0, 0, 0, 0, 0};
> 
> I don't know how this is any better than using memset...
> 
> Also, you can do
> 
> 	... start = { };
> 
> which is certainly the only other alternative to memset, AFAIK.
> 
> But whatever you do, you need to look at the resulting asm the compiler
> generates. So let's do that:

I'm ok with Boris' version, I'm not a fan of having to count zeros.  I used
memset() to defer initialization until after the various sanity checks, and
out of habit.
Christophe Leroy April 7, 2021, 5:06 p.m. UTC | #4
Le 07/04/2021 à 19:05, Sean Christopherson a écrit :
> On Wed, Apr 07, 2021, Borislav Petkov wrote:
>> First of all, I'd strongly suggest you trim your emails when you reply -
>> that would be much appreciated.
>>
>> On Wed, Apr 07, 2021 at 07:24:54AM +0200, Christophe Leroy wrote:
>>>> @@ -258,7 +240,7 @@ 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 sev_data_launch_start start = {0, 0, 0, 0, 0, 0, 0};
>>
>> I don't know how this is any better than using memset...
>>
>> Also, you can do
>>
>> 	... start = { };
>>
>> which is certainly the only other alternative to memset, AFAIK.
>>
>> But whatever you do, you need to look at the resulting asm the compiler
>> generates. So let's do that:
> 
> I'm ok with Boris' version, I'm not a fan of having to count zeros.  I used
> memset() to defer initialization until after the various sanity checks, and
> out of habit.
> 

Yes I also like Boris' version 	... start = { };  better than mine.
Borislav Petkov April 7, 2021, 5:34 p.m. UTC | #5
On Wed, Apr 07, 2021 at 05:05:07PM +0000, Sean Christopherson wrote:
> I used memset() to defer initialization until after the various sanity
> checks,

I'd actually vote for that too - I don't like doing stuff which is not
going to be used. I.e., don't change what you have.
Paolo Bonzini April 17, 2021, 12:45 p.m. UTC | #6
On 07/04/21 19:34, Borislav Petkov wrote:
> On Wed, Apr 07, 2021 at 05:05:07PM +0000, Sean Christopherson wrote:
>> I used memset() to defer initialization until after the various sanity
>> checks,
> 
> I'd actually vote for that too - I don't like doing stuff which is not
> going to be used. I.e., don't change what you have.

It's three votes for that then. :)

Sean, I squashed in this change

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index ec4c01807272..a4d0ca8c4710 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1039,21 +1039,14 @@ static int sev_get_attestation_report(struct kvm *kvm, struct kvm_sev_cmd *argp)
  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;
+	struct sev_data_send_cancel data;
  	int ret;
  
  	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);
  }
  
  int svm_mem_enc_op(struct kvm *kvm, void __user *argp)

to handle SV_CMD_SEND_CANCEL which I merged before this series.

Paolo
diff mbox series

Patch

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 5457138c7347..316fd39c7aef 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -150,35 +150,22 @@  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)
@@ -216,19 +203,14 @@  static int sev_guest_init(struct kvm *kvm, struct kvm_sev_cmd *argp)
 
 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;
 }
@@ -258,7 +240,7 @@  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;
@@ -270,20 +252,16 @@  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;
@@ -294,40 +272,38 @@  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;
 }
 
@@ -446,7 +422,7 @@  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;
 
@@ -456,20 +432,14 @@  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
@@ -477,6 +447,9 @@  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;
 
@@ -491,10 +464,9 @@  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;
 
@@ -510,8 +482,6 @@  static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	}
 	/* unlock the user pages */
 	sev_unpin_memory(kvm, inpages, npages);
-e_free:
-	kfree(data);
 	return ret;
 }
 
@@ -563,16 +533,14 @@  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);
@@ -580,7 +548,7 @@  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
@@ -590,27 +558,25 @@  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;
@@ -622,9 +588,7 @@  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)
@@ -632,23 +596,20 @@  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.
@@ -665,63 +626,50 @@  static int sev_launch_measure(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	}
 
 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;
 }
 
@@ -730,23 +678,17 @@  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.reserved = 0;
+	data.handle = sev->handle;
+	data.dst_addr = dst;
+	data.src_addr = src;
+	data.len = size;
 
-	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,
@@ -966,7 +908,7 @@  static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
 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;
@@ -998,41 +940,36 @@  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++) {
@@ -1047,7 +984,7 @@  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;
@@ -1059,9 +996,7 @@  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)
@@ -1069,23 +1004,20 @@  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.
 	 */
@@ -1101,13 +1033,11 @@  static int sev_get_attestation_report(struct kvm *kvm, struct kvm_sev_cmd *argp)
 	}
 
 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;
 }