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| author | Kristen Carlson Accardi <kristen@linux.intel.com> | 2022-11-15 19:16:26 +0300 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2022-12-02 16:59:56 +0300 |
| commit | 89e927bbcd45d507e5612ef72fda04182e544a38 (patch) | |
| tree | 014facff69c8f3b34e9336d1ba56c316f3b6842d /arch/x86/kernel/cpu/sgx/encl.c | |
| parent | 16a7fe3728a8b832ef0d1add66875a666b1f24fc (diff) | |
| download | linux-89e927bbcd45d507e5612ef72fda04182e544a38.tar.xz | |
x86/sgx: Replace kmap/kunmap_atomic() calls
kmap_local_page() is the preferred way to create temporary mappings when it
is feasible, because the mappings are thread-local and CPU-local.
kmap_local_page() uses per-task maps rather than per-CPU maps. This in
effect removes the need to disable preemption on the local CPU while the
mapping is active, and thus vastly reduces overall system latency. It is
also valid to take pagefaults within the mapped region.
The use of kmap_atomic() in the SGX code was not an explicit design choice
to disable page faults or preemption, and there is no compelling design
reason to using kmap_atomic() vs. kmap_local_page().
Signed-off-by: Kristen Carlson Accardi <kristen@linux.intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Reviewed-by: Fabio M. De Francesco <fmdefrancesco@gmail.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Link: https://lore.kernel.org/linux-sgx/Y0biN3%2FJsZMa0yUr@kernel.org/
Link: https://lore.kernel.org/r/20221115161627.4169428-1-kristen@linux.intel.com
Diffstat (limited to 'arch/x86/kernel/cpu/sgx/encl.c')
| -rw-r--r-- | arch/x86/kernel/cpu/sgx/encl.c | 12 |
1 files changed, 6 insertions, 6 deletions
diff --git a/arch/x86/kernel/cpu/sgx/encl.c b/arch/x86/kernel/cpu/sgx/encl.c index 2c258255a629..68f8b18d2278 100644 --- a/arch/x86/kernel/cpu/sgx/encl.c +++ b/arch/x86/kernel/cpu/sgx/encl.c @@ -160,8 +160,8 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page, return ret; pginfo.addr = encl_page->desc & PAGE_MASK; - pginfo.contents = (unsigned long)kmap_atomic(b.contents); - pcmd_page = kmap_atomic(b.pcmd); + pginfo.contents = (unsigned long)kmap_local_page(b.contents); + pcmd_page = kmap_local_page(b.pcmd); pginfo.metadata = (unsigned long)pcmd_page + b.pcmd_offset; if (secs_page) @@ -187,8 +187,8 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page, */ pcmd_page_empty = !memchr_inv(pcmd_page, 0, PAGE_SIZE); - kunmap_atomic(pcmd_page); - kunmap_atomic((void *)(unsigned long)pginfo.contents); + kunmap_local(pcmd_page); + kunmap_local((void *)(unsigned long)pginfo.contents); get_page(b.pcmd); sgx_encl_put_backing(&b); @@ -197,10 +197,10 @@ static int __sgx_encl_eldu(struct sgx_encl_page *encl_page, if (pcmd_page_empty && !reclaimer_writing_to_pcmd(encl, pcmd_first_page)) { sgx_encl_truncate_backing_page(encl, PFN_DOWN(page_pcmd_off)); - pcmd_page = kmap_atomic(b.pcmd); + pcmd_page = kmap_local_page(b.pcmd); if (memchr_inv(pcmd_page, 0, PAGE_SIZE)) pr_warn("PCMD page not empty after truncate.\n"); - kunmap_atomic(pcmd_page); + kunmap_local(pcmd_page); } put_page(b.pcmd); |