[PATCH v3 09/16] powerpc/pseries/svm: Use shared memory for Debug Trace Log (DTL)
From: Thiago Jung Bauermann <hidden>
Date: 2019-08-06 05:25:47
Also in:
lkml
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
From: Anshuman Khandual <redacted> Secure guests need to share the DTL buffers with the hypervisor. To that end, use a kmem_cache constructor which converts the underlying buddy allocated SLUB cache pages into shared memory. Signed-off-by: Anshuman Khandual <redacted> Signed-off-by: Thiago Jung Bauermann <redacted> --- arch/powerpc/include/asm/svm.h | 5 ++++ arch/powerpc/platforms/pseries/Makefile | 1 + arch/powerpc/platforms/pseries/setup.c | 5 +++- arch/powerpc/platforms/pseries/svm.c | 40 +++++++++++++++++++++++++ 4 files changed, 50 insertions(+), 1 deletion(-)
diff --git a/arch/powerpc/include/asm/svm.h b/arch/powerpc/include/asm/svm.h
index fef3740f46a6..f253116c31fc 100644
--- a/arch/powerpc/include/asm/svm.h
+++ b/arch/powerpc/include/asm/svm.h@@ -15,6 +15,9 @@ static inline bool is_secure_guest(void) return mfmsr() & MSR_S; } +void dtl_cache_ctor(void *addr); +#define get_dtl_cache_ctor() (is_secure_guest() ? dtl_cache_ctor : NULL) + #else /* CONFIG_PPC_SVM */ static inline bool is_secure_guest(void)
@@ -22,5 +25,7 @@ static inline bool is_secure_guest(void) return false; } +#define get_dtl_cache_ctor() NULL + #endif /* CONFIG_PPC_SVM */ #endif /* _ASM_POWERPC_SVM_H */
diff --git a/arch/powerpc/platforms/pseries/Makefile b/arch/powerpc/platforms/pseries/Makefile
index ab3d59aeacca..a420ef4c9d8e 100644
--- a/arch/powerpc/platforms/pseries/Makefile
+++ b/arch/powerpc/platforms/pseries/Makefile@@ -26,6 +26,7 @@ obj-$(CONFIG_IBMVIO) += vio.o obj-$(CONFIG_IBMEBUS) += ibmebus.o obj-$(CONFIG_PAPR_SCM) += papr_scm.o obj-$(CONFIG_PPC_SPLPAR) += vphn.o +obj-$(CONFIG_PPC_SVM) += svm.o ifdef CONFIG_PPC_PSERIES obj-$(CONFIG_SUSPEND) += suspend.o
diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c
index f5940cc71c37..d8930c3a8a11 100644
--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c@@ -69,6 +69,7 @@ #include <asm/security_features.h> #include <asm/asm-const.h> #include <asm/swiotlb.h> +#include <asm/svm.h> #include "pseries.h" #include "../../../../drivers/pci/pci.h"
@@ -297,8 +298,10 @@ static inline int alloc_dispatch_logs(void) static int alloc_dispatch_log_kmem_cache(void) { + void (*ctor)(void *) = get_dtl_cache_ctor(); + dtl_cache = kmem_cache_create("dtl", DISPATCH_LOG_BYTES, - DISPATCH_LOG_BYTES, 0, NULL); + DISPATCH_LOG_BYTES, 0, ctor); if (!dtl_cache) { pr_warn("Failed to create dispatch trace log buffer cache\n"); pr_warn("Stolen time statistics will be unreliable\n");
diff --git a/arch/powerpc/platforms/pseries/svm.c b/arch/powerpc/platforms/pseries/svm.c
new file mode 100644
index 000000000000..c508196f7c83
--- /dev/null
+++ b/arch/powerpc/platforms/pseries/svm.c@@ -0,0 +1,40 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * Secure VM platform + * + * Copyright 2019 IBM Corporation + * Author: Anshuman Khandual <khandual@linux.vnet.ibm.com> + */ + +#include <linux/mm.h> +#include <asm/ultravisor.h> + +/* There's one dispatch log per CPU. */ +#define NR_DTL_PAGE (DISPATCH_LOG_BYTES * CONFIG_NR_CPUS / PAGE_SIZE) + +static struct page *dtl_page_store[NR_DTL_PAGE]; +static long dtl_nr_pages; + +static bool is_dtl_page_shared(struct page *page) +{ + long i; + + for (i = 0; i < dtl_nr_pages; i++) + if (dtl_page_store[i] == page) + return true; + + return false; +} + +void dtl_cache_ctor(void *addr) +{ + unsigned long pfn = PHYS_PFN(__pa(addr)); + struct page *page = pfn_to_page(pfn); + + if (!is_dtl_page_shared(page)) { + dtl_page_store[dtl_nr_pages] = page; + dtl_nr_pages++; + WARN_ON(dtl_nr_pages >= NR_DTL_PAGE); + uv_share_page(pfn, 1); + } +}