diff options
Diffstat (limited to 'system/xen/xsa/xsa402-4.16-4.patch')
| -rw-r--r-- | system/xen/xsa/xsa402-4.16-4.patch | 83 |
1 files changed, 0 insertions, 83 deletions
diff --git a/system/xen/xsa/xsa402-4.16-4.patch b/system/xen/xsa/xsa402-4.16-4.patch deleted file mode 100644 index 21109225d7..0000000000 --- a/system/xen/xsa/xsa402-4.16-4.patch +++ /dev/null @@ -1,83 +0,0 @@ -From: Andrew Cooper <andrew.cooper3@citrix.com> -Subject: x86/amd: Work around CLFLUSH ordering on older parts - -On pre-CLFLUSHOPT AMD CPUs, CLFLUSH is weakely ordered with everything, -including reads and writes to the address, and LFENCE/SFENCE instructions. - -This creates a multitude of problematic corner cases, laid out in the manual. -Arrange to use MFENCE on both sides of the CLFLUSH to force proper ordering. - -This is part of XSA-402. - -Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> -Reviewed-by: Jan Beulich <jbeulich@suse.com> - -diff --git a/xen/arch/x86/cpu/amd.c b/xen/arch/x86/cpu/amd.c -index a8e37dbb1f5c..b3b9a0df5fed 100644 ---- a/xen/arch/x86/cpu/amd.c -+++ b/xen/arch/x86/cpu/amd.c -@@ -812,6 +812,14 @@ static void init_amd(struct cpuinfo_x86 *c) - if (!cpu_has_lfence_dispatch) - __set_bit(X86_FEATURE_MFENCE_RDTSC, c->x86_capability); - -+ /* -+ * On pre-CLFLUSHOPT AMD CPUs, CLFLUSH is weakly ordered with -+ * everything, including reads and writes to address, and -+ * LFENCE/SFENCE instructions. -+ */ -+ if (!cpu_has_clflushopt) -+ setup_force_cpu_cap(X86_BUG_CLFLUSH_MFENCE); -+ - switch(c->x86) - { - case 0xf ... 0x11: -diff --git a/xen/arch/x86/flushtlb.c b/xen/arch/x86/flushtlb.c -index 0c912b8669f8..dcbb4064012e 100644 ---- a/xen/arch/x86/flushtlb.c -+++ b/xen/arch/x86/flushtlb.c -@@ -259,6 +259,13 @@ unsigned int flush_area_local(const void *va, unsigned int flags) - return flags; - } - -+/* -+ * On pre-CLFLUSHOPT AMD CPUs, CLFLUSH is weakly ordered with everything, -+ * including reads and writes to address, and LFENCE/SFENCE instructions. -+ * -+ * This function only works safely after alternatives have run. Luckily, at -+ * the time of writing, we don't flush the caches that early. -+ */ - void cache_flush(const void *addr, unsigned int size) - { - /* -@@ -268,6 +275,8 @@ void cache_flush(const void *addr, unsigned int size) - unsigned int clflush_size = current_cpu_data.x86_clflush_size ?: 16; - const void *end = addr + size; - -+ alternative("", "mfence", X86_BUG_CLFLUSH_MFENCE); -+ - addr -= (unsigned long)addr & (clflush_size - 1); - for ( ; addr < end; addr += clflush_size ) - { -@@ -283,7 +292,9 @@ void cache_flush(const void *addr, unsigned int size) - [p] "m" (*(const char *)(addr))); - } - -- alternative("", "sfence", X86_FEATURE_CLFLUSHOPT); -+ alternative_2("", -+ "sfence", X86_FEATURE_CLFLUSHOPT, -+ "mfence", X86_BUG_CLFLUSH_MFENCE); - } - - void cache_writeback(const void *addr, unsigned int size) -diff --git a/xen/include/asm-x86/cpufeatures.h b/xen/include/asm-x86/cpufeatures.h -index 7413febd7ad8..ff3157d52d13 100644 ---- a/xen/include/asm-x86/cpufeatures.h -+++ b/xen/include/asm-x86/cpufeatures.h -@@ -47,6 +47,7 @@ XEN_CPUFEATURE(XEN_IBT, X86_SYNTH(27)) /* Xen uses CET Indirect Branch - - #define X86_BUG_FPU_PTRS X86_BUG( 0) /* (F)X{SAVE,RSTOR} doesn't save/restore FOP/FIP/FDP. */ - #define X86_BUG_NULL_SEG X86_BUG( 1) /* NULL-ing a selector preserves the base and limit. */ -+#define X86_BUG_CLFLUSH_MFENCE X86_BUG( 2) /* MFENCE needed to serialise CLFLUSH */ - - /* Total number of capability words, inc synth and bug words. */ - #define NCAPINTS (FSCAPINTS + X86_NR_SYNTH + X86_NR_BUG) /* N 32-bit words worth of info */ |