Currently SGX does not have a global counter to count the active users from userspace or hypervisor. Implement such a counter, sgx_usage_count. It will be used by the driver when attempting to call EUPDATESVN SGX instruction.
Note: the sgx_inc_usage_count prototype is defined to return int for the cleanliness of the follow-up patches. When the EUPDATESVN SGX instruction will be enabled in the follow-up patch, the sgx_inc_usage_count will start to return int. Suggested-by: Sean Christopherson <[email protected]> Signed-off-by: Elena Reshetova <[email protected]> --- arch/x86/kernel/cpu/sgx/driver.c | 19 ++++++++++++++++++- arch/x86/kernel/cpu/sgx/encl.c | 1 + arch/x86/kernel/cpu/sgx/main.c | 13 +++++++++++++ arch/x86/kernel/cpu/sgx/sgx.h | 3 +++ arch/x86/kernel/cpu/sgx/virt.c | 21 ++++++++++++++++++++- 5 files changed, 55 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/driver.c b/arch/x86/kernel/cpu/sgx/driver.c index 9aa48f455c54..79d6020dfe9c 100644 --- a/arch/x86/kernel/cpu/sgx/driver.c +++ b/arch/x86/kernel/cpu/sgx/driver.c @@ -41,6 +41,23 @@ static int __sgx_open(struct inode *inode, struct file *file) return 0; } +static int sgx_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = sgx_inc_usage_count(); + if (ret) + return ret; + + ret = __sgx_open(inode, file); + if (ret) { + sgx_dec_usage_count(); + return ret; + } + + return 0; +} + static int sgx_release(struct inode *inode, struct file *file) { struct sgx_encl *encl = file->private_data; @@ -126,7 +143,7 @@ static long sgx_compat_ioctl(struct file *filep, unsigned int cmd, static const struct file_operations sgx_encl_fops = { .owner = THIS_MODULE, - .open = __sgx_open, + .open = sgx_open, .release = sgx_release, .unlocked_ioctl = sgx_ioctl, #ifdef CONFIG_COMPAT diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 279148e72459..3b54889ae4a4 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -765,6 +765,7 @@ void sgx_encl_release(struct kref *ref) WARN_ON_ONCE(encl->secs.epc_page); kfree(encl); + sgx_dec_usage_count(); } /* diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 2de01b379aa3..ccb81a649d1b 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -917,6 +917,19 @@ int sgx_set_attribute(unsigned long *allowed_attributes, } EXPORT_SYMBOL_GPL(sgx_set_attribute); +/* Counter to count the active SGX users */ +static int __maybe_unused sgx_usage_count; + +int sgx_inc_usage_count(void) +{ + return 0; +} + +void sgx_dec_usage_count(void) +{ + return; +} + static int __init sgx_init(void) { int ret; diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index d2dad21259a8..f5940393d9bd 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -102,6 +102,9 @@ static inline int __init sgx_vepc_init(void) } #endif +int sgx_inc_usage_count(void); +void sgx_dec_usage_count(void); + void sgx_update_lepubkeyhash(u64 *lepubkeyhash); #endif /* _X86_SGX_H */ diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c index d8fdf7f39215..d6bff258d761 100644 --- a/arch/x86/kernel/cpu/sgx/virt.c +++ b/arch/x86/kernel/cpu/sgx/virt.c @@ -255,6 +255,7 @@ static int sgx_vepc_release(struct inode *inode, struct file *file) xa_destroy(&vepc->page_array); kfree(vepc); + sgx_dec_usage_count(); return 0; } @@ -265,6 +266,7 @@ static int __sgx_vepc_open(struct inode *inode, struct file *file) vepc = kzalloc(sizeof(struct sgx_vepc), GFP_KERNEL); if (!vepc) return -ENOMEM; + mutex_init(&vepc->lock); xa_init(&vepc->page_array); @@ -273,6 +275,23 @@ static int __sgx_vepc_open(struct inode *inode, struct file *file) return 0; } +static int sgx_vepc_open(struct inode *inode, struct file *file) +{ + int ret; + + ret = sgx_inc_usage_count(); + if (ret) + return ret; + + ret = __sgx_vepc_open(inode, file); + if (ret) { + sgx_dec_usage_count(); + return ret; + } + + return 0; +} + static long sgx_vepc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) { @@ -291,7 +310,7 @@ static long sgx_vepc_ioctl(struct file *file, static const struct file_operations sgx_vepc_fops = { .owner = THIS_MODULE, - .open = __sgx_vepc_open, + .open = sgx_vepc_open, .unlocked_ioctl = sgx_vepc_ioctl, .compat_ioctl = sgx_vepc_ioctl, .release = sgx_vepc_release, -- 2.45.2
