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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] x86/amd: split LFENCE dispatch serializing setup logic into helper
commit 3e9460ec93341fa6a80ecf99832aa5d9975339c9
Author: Roger Pau Monné <roger.pau@xxxxxxxxxx>
AuthorDate: Thu Apr 15 13:45:09 2021 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Thu Apr 15 13:45:09 2021 +0200
x86/amd: split LFENCE dispatch serializing setup logic into helper
Split the logic to attempt to setup LFENCE to be dispatch serializing
on AMD into a helper, so it can be shared with Hygon.
No functional change intended.
Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Reviewed-by: Andrew Cooper <andrew.cooper3@xxxxxxxxxx>
---
xen/arch/x86/cpu/amd.c | 62 ++++++++++++++++++++++++++----------------------
xen/arch/x86/cpu/cpu.h | 1 +
xen/arch/x86/cpu/hygon.c | 27 +--------------------
3 files changed, 36 insertions(+), 54 deletions(-)
diff --git a/xen/arch/x86/cpu/amd.c b/xen/arch/x86/cpu/amd.c
index 8bc51bec10..9c8dcd91ee 100644
--- a/xen/arch/x86/cpu/amd.c
+++ b/xen/arch/x86/cpu/amd.c
@@ -642,6 +642,38 @@ void early_init_amd(struct cpuinfo_x86 *c)
ctxt_switch_levelling(NULL);
}
+void amd_init_lfence(struct cpuinfo_x86 *c)
+{
+ uint64_t value;
+
+ /*
+ * Attempt to set lfence to be Dispatch Serialising. This MSR almost
+ * certainly isn't virtualised (and Xen at least will leak the real
+ * value in but silently discard writes), as well as being per-core
+ * rather than per-thread, so do a full safe read/write/readback cycle
+ * in the worst case.
+ */
+ if (rdmsr_safe(MSR_AMD64_DE_CFG, value))
+ /* Unable to read. Assume the safer default. */
+ __clear_bit(X86_FEATURE_LFENCE_DISPATCH,
+ c->x86_capability);
+ else if (value & AMD64_DE_CFG_LFENCE_SERIALISE)
+ /* Already dispatch serialising. */
+ __set_bit(X86_FEATURE_LFENCE_DISPATCH,
+ c->x86_capability);
+ else if (wrmsr_safe(MSR_AMD64_DE_CFG,
+ value | AMD64_DE_CFG_LFENCE_SERIALISE) ||
+ rdmsr_safe(MSR_AMD64_DE_CFG, value) ||
+ !(value & AMD64_DE_CFG_LFENCE_SERIALISE))
+ /* Attempt to set failed. Assume the safer default. */
+ __clear_bit(X86_FEATURE_LFENCE_DISPATCH,
+ c->x86_capability);
+ else
+ /* Successfully enabled! */
+ __set_bit(X86_FEATURE_LFENCE_DISPATCH,
+ c->x86_capability);
+}
+
static void init_amd(struct cpuinfo_x86 *c)
{
u32 l, h;
@@ -686,37 +718,11 @@ static void init_amd(struct cpuinfo_x86 *c)
if (c == &boot_cpu_data && !cpu_has(c, X86_FEATURE_RSTR_FP_ERR_PTRS))
setup_force_cpu_cap(X86_BUG_FPU_PTRS);
- /*
- * Attempt to set lfence to be Dispatch Serialising. This MSR almost
- * certainly isn't virtualised (and Xen at least will leak the real
- * value in but silently discard writes), as well as being per-core
- * rather than per-thread, so do a full safe read/write/readback cycle
- * in the worst case.
- */
if (c->x86 == 0x0f || c->x86 == 0x11)
/* Always dispatch serialising on this hardare. */
__set_bit(X86_FEATURE_LFENCE_DISPATCH, c->x86_capability);
- else /* Implicily "== 0x10 || >= 0x12" by being 64bit. */ {
- if (rdmsr_safe(MSR_AMD64_DE_CFG, value))
- /* Unable to read. Assume the safer default. */
- __clear_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
- else if (value & AMD64_DE_CFG_LFENCE_SERIALISE)
- /* Already dispatch serialising. */
- __set_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
- else if (wrmsr_safe(MSR_AMD64_DE_CFG,
- value | AMD64_DE_CFG_LFENCE_SERIALISE) ||
- rdmsr_safe(MSR_AMD64_DE_CFG, value) ||
- !(value & AMD64_DE_CFG_LFENCE_SERIALISE))
- /* Attempt to set failed. Assume the safer default. */
- __clear_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
- else
- /* Successfully enabled! */
- __set_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
- }
+ else /* Implicily "== 0x10 || >= 0x12" by being 64bit. */
+ amd_init_lfence(c);
/*
* If the user has explicitly chosen to disable Memory Disambiguation
diff --git a/xen/arch/x86/cpu/cpu.h b/xen/arch/x86/cpu/cpu.h
index 1992596d1b..1ac3b2867a 100644
--- a/xen/arch/x86/cpu/cpu.h
+++ b/xen/arch/x86/cpu/cpu.h
@@ -20,3 +20,4 @@ extern bool detect_extended_topology(struct cpuinfo_x86 *c);
void early_init_amd(struct cpuinfo_x86 *c);
void amd_log_freq(const struct cpuinfo_x86 *c);
+void amd_init_lfence(struct cpuinfo_x86 *c);
diff --git a/xen/arch/x86/cpu/hygon.c b/xen/arch/x86/cpu/hygon.c
index 46293f1f36..2272e1113f 100644
--- a/xen/arch/x86/cpu/hygon.c
+++ b/xen/arch/x86/cpu/hygon.c
@@ -32,32 +32,7 @@ static void init_hygon(struct cpuinfo_x86 *c)
{
unsigned long long value;
- /*
- * Attempt to set lfence to be Dispatch Serialising. This MSR almost
- * certainly isn't virtualised (and Xen at least will leak the real
- * value in but silently discard writes), as well as being per-core
- * rather than per-thread, so do a full safe read/write/readback cycle
- * in the worst case.
- */
- if (rdmsr_safe(MSR_AMD64_DE_CFG, value))
- /* Unable to read. Assume the safer default. */
- __clear_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
- else if (value & AMD64_DE_CFG_LFENCE_SERIALISE)
- /* Already dispatch serialising. */
- __set_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
- else if (wrmsr_safe(MSR_AMD64_DE_CFG,
- value | AMD64_DE_CFG_LFENCE_SERIALISE) ||
- rdmsr_safe(MSR_AMD64_DE_CFG, value) ||
- !(value & AMD64_DE_CFG_LFENCE_SERIALISE))
- /* Attempt to set failed. Assume the safer default. */
- __clear_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
- else
- /* Successfully enabled! */
- __set_bit(X86_FEATURE_LFENCE_DISPATCH,
- c->x86_capability);
+ amd_init_lfence(c);
/*
* If the user has explicitly chosen to disable Memory Disambiguation
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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