[PATCH v3 12/25] x86/sgx: Add helper to update SGX_LEPUBKEYHASHn MSRs

Kai Huang
2021-03-19T07:24:34Z

Add a helper to update SGX_LEPUBKEYHASHn MSRs. SGX virtualization also
needs to update those MSRs based on guest's "virtual" SGX_LEPUBKEYHASHn
before EINIT from guest.

Acked-by: Dave Hansen <dave.hansen@intel.com>
Acked-by: Jarkko Sakkinen <jarkko@kernel.org>
Signed-off-by: Kai Huang <kai.huang@intel.com>
---
arch/x86/kernel/cpu/sgx/ioctl.c | 5 ++---
arch/x86/kernel/cpu/sgx/main.c | 17 +++++++++++++++++
arch/x86/kernel/cpu/sgx/sgx.h | 2 ++
3 files changed, 21 insertions(+), 3 deletions(-)

diff --git a/arch/x86/kernel/cpu/sgx/ioctl.c b/arch/x86/kernel/cpu/sgx/ioctl.c
index dc18ced04ad8..2a0aed446d6c 100644
--- a/arch/x86/kernel/cpu/sgx/ioctl.c
+++ b/arch/x86/kernel/cpu/sgx/ioctl.c
@@ -495,7 +495,7 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,
void *token)
{
u64 mrsigner[4];
- int i, j, k;
+ int i, j;
void *addr;
int ret;

@@ -544,8 +544,7 @@ static int sgx_encl_init(struct sgx_encl *encl, struct sgx_sigstruct *sigstruct,

preempt_disable();

- for (k = 0; k < 4; k++)
- wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + k, mrsigner[k]);
+ sgx_update_lepubkeyhash(mrsigner);

ret = __einit(sigstruct, token, addr);

diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c
index b73114150ff8..b95168427056 100644
--- a/arch/x86/kernel/cpu/sgx/main.c
+++ b/arch/x86/kernel/cpu/sgx/main.c
@@ -727,6 +727,23 @@ static bool __init sgx_page_cache_init(void)
return true;
}

+
+/*
+ * Update the SGX_LEPUBKEYHASH MSRs to the values specified by caller.
+ * Bare-metal driver requires to update them to hash of enclave's signer
+ * before EINIT. KVM needs to update them to guest's virtual MSR values
+ * before doing EINIT from guest.
+ */
+void sgx_update_lepubkeyhash(u64 *lepubkeyhash)
+{
+ int i;
+
+ WARN_ON_ONCE(preemptible());
+
+ for (i = 0; i < 4; i++)
+ wrmsrl(MSR_IA32_SGXLEPUBKEYHASH0 + i, lepubkeyhash[i]);
+}
+
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 5086b240d269..f0f2a92bb8d0 100644
--- a/arch/x86/kernel/cpu/sgx/sgx.h
+++ b/arch/x86/kernel/cpu/sgx/sgx.h
@@ -89,4 +89,6 @@ static inline int __init sgx_vepc_init(void)
}
#endif

+void sgx_update_lepubkeyhash(u64 *lepubkeyhash);
+
#endif /* _X86_SGX_H */
--
2.30.2