[PATCH v5 08/10] KVM: SVM: move sev_issue_cmd_external_user to new API

Dionna Glaze
2024-11-07T23:29:01Z

ccp now prefers all calls from external drivers to dominate all calls
into the driver on behalf of a user with a successful
sev_check_external_user call.

CC: Sean Christopherson <seanjc@google.com>
CC: Paolo Bonzini <pbonzini@redhat.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Ingo Molnar <mingo@redhat.com>
CC: Borislav Petkov <bp@alien8.de>
CC: Dave Hansen <dave.hansen@linux.intel.com>
CC: Ashish Kalra <ashish.kalra@amd.com>
CC: Tom Lendacky <thomas.lendacky@amd.com>
CC: John Allen <john.allen@amd.com>
CC: Herbert Xu <herbert@gondor.apana.org.au>
CC: "David S. Miller" <davem@davemloft.net>
CC: Michael Roth <michael.roth@amd.com>
CC: Luis Chamberlain <mcgrof@kernel.org>
CC: Russ Weight <russ.weight@linux.dev>
CC: Danilo Krummrich <dakr@redhat.com>
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: "Rafael J. Wysocki" <rafael@kernel.org>
CC: Tianfei zhang <tianfei.zhang@intel.com>
CC: Alexey Kardashevskiy <aik@amd.com>

Signed-off-by: Dionna Glaze <dionnaglaze@google.com>
---
arch/x86/kvm/svm/sev.c | 18 +++++++++++++++---
drivers/crypto/ccp/sev-dev.c | 12 ------------
include/linux/psp-sev.h | 27 ---------------------------
3 files changed, 15 insertions(+), 42 deletions(-)

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index d0e0152aefb32..cea41b8cdabe4 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -528,21 +528,33 @@ static int sev_bind_asid(struct kvm *kvm, unsigned int handle, int *error)
return ret;
}

-static int __sev_issue_cmd(int fd, int id, void *data, int *error)
+static int sev_check_external_user(int fd)
{
struct fd f;
- int ret;
+ int ret = 0;

f = fdget(fd);
if (!fd_file(f))
return -EBADF;

- ret = sev_issue_cmd_external_user(fd_file(f), id, data, error);
+ if (!file_is_sev(fd_file(f)))
+ ret = -EBADF;

fdput(f);
return ret;
}

+static int __sev_issue_cmd(int fd, int id, void *data, int *error)
+{
+ int ret;
+
+ ret = sev_check_external_user(fd);
+ if (ret)
+ return ret;
+
+ return sev_do_cmd(id, data, error);
+}
+
static int sev_issue_cmd(struct kvm *kvm, int id, void *data, int *error)
{
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
diff --git a/drivers/crypto/ccp/sev-dev.c b/drivers/crypto/ccp/sev-dev.c
index f92e6a222da8a..67f6425b7ed07 100644
--- a/drivers/crypto/ccp/sev-dev.c
+++ b/drivers/crypto/ccp/sev-dev.c
@@ -2493,18 +2493,6 @@ bool file_is_sev(struct file *p)
}
EXPORT_SYMBOL_GPL(file_is_sev);

-int sev_issue_cmd_external_user(struct file *filep, unsigned int cmd,
- void *data, int *error)
-{
- int rc = file_is_sev(filep) ? 0 : -EBADF;
-
- if (rc)
- return rc;
-
- return sev_do_cmd(cmd, data, error);
-}
-EXPORT_SYMBOL_GPL(sev_issue_cmd_external_user);
-
void sev_pci_init(void)
{
struct sev_device *sev = psp_master->sev_data;
diff --git a/include/linux/psp-sev.h b/include/linux/psp-sev.h
index ed85c0cfcfcbe..b4164d3600702 100644
--- a/include/linux/psp-sev.h
+++ b/include/linux/psp-sev.h
@@ -860,30 +860,6 @@ int sev_platform_init(struct sev_platform_init_args *args);
*/
int sev_platform_status(struct sev_user_data_status *status, int *error);

-/**
- * sev_issue_cmd_external_user - issue SEV command by other driver with a file
- * handle.
- *
- * This function can be used by other drivers to issue a SEV command on
- * behalf of userspace. The caller must pass a valid SEV file descriptor
- * so that we know that it has access to SEV device.
- *
- * @filep - SEV device file pointer
- * @cmd - command to issue
- * @data - command buffer
- * @error: SEV command return code
- *
- * 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
- * -%EBADF if the file pointer is bad or does not grant access
- */
-int sev_issue_cmd_external_user(struct file *filep, unsigned int id,
- void *data, int *error);
-
/**
* file_is_sev - returns whether a file pointer is for the SEV device
*
@@ -1043,9 +1019,6 @@ sev_guest_activate(struct sev_data_activate *data, int *error) { return -ENODEV;

static inline int sev_guest_df_flush(int *error) { return -ENODEV; }

-static inline int
-sev_issue_cmd_external_user(struct file *filep, unsigned int id, void *data, int *error) { return -ENODEV; }
-
static inline bool file_is_sev(struct file *filep) { return false; }

static inline void *psp_copy_user_blob(u64 __user uaddr, u32 len) { return ERR_PTR(-EINVAL); }
--
2.47.0.277.g8800431eea-goog