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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH 2/6] x86/xsaves: enable xsaves/xrstors in xen
This patch uses xsaves/xrstors instead of xsaveopt/xrstor
when perform task switch in xen if the feature is supported
in hardware.
Please note that xsaves/xrstors only use compact format.
Signed-off-by: Shuai Ruan <shuai.ruan@xxxxxxxxx>
---
xen/arch/x86/xstate.c | 83 ++++++++++++++++++++++++++++----------------
xen/include/asm-x86/xstate.h | 3 +-
2 files changed, 55 insertions(+), 31 deletions(-)
diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c
index e34eda3..ff67986 100644
--- a/xen/arch/x86/xstate.c
+++ b/xen/arch/x86/xstate.c
@@ -14,6 +14,7 @@
#include <asm/xstate.h>
#include <asm/asm_defns.h>
+#define XSTATE_COMPACTION_ENABLED (1ULL << 63)
static bool_t __read_mostly cpu_has_xsaveopt;
static bool_t __read_mostly cpu_has_xsavec;
bool_t __read_mostly cpu_has_xgetbv1;
@@ -102,7 +103,9 @@ void xsave(struct vcpu *v, uint64_t mask)
typeof(ptr->fpu_sse.fip.sel) fcs = ptr->fpu_sse.fip.sel;
typeof(ptr->fpu_sse.fdp.sel) fds = ptr->fpu_sse.fdp.sel;
- if ( cpu_has_xsaveopt )
+ if ( cpu_has_xsaves )
+ xsaves(lmask, hmask, ptr);
+ else if ( cpu_has_xsaveopt )
{
/*
* xsaveopt may not write the FPU portion even when the respective
@@ -155,7 +158,9 @@ void xsave(struct vcpu *v, uint64_t mask)
}
else
{
- if ( cpu_has_xsaveopt )
+ if ( cpu_has_xsaves )
+ xsaves(lmask, hmask, ptr);
+ else if ( cpu_has_xsaveopt )
asm volatile ( ".byte 0x0f,0xae,0x37"
: "=m" (*ptr)
: "a" (lmask), "d" (hmask), "D" (ptr) );
@@ -198,36 +203,54 @@ void xrstor(struct vcpu *v, uint64_t mask)
switch ( __builtin_expect(ptr->fpu_sse.x[FPU_WORD_SIZE_OFFSET], 8) )
{
default:
- asm volatile ( "1: .byte 0x48,0x0f,0xae,0x2f\n"
- ".section .fixup,\"ax\" \n"
- "2: mov %5,%%ecx \n"
- " xor %1,%1 \n"
- " rep stosb \n"
- " lea %2,%0 \n"
- " mov %3,%1 \n"
- " jmp 1b \n"
- ".previous \n"
- _ASM_EXTABLE(1b, 2b)
- : "+&D" (ptr), "+&a" (lmask)
- : "m" (*ptr), "g" (lmask), "d" (hmask),
- "m" (xsave_cntxt_size)
- : "ecx" );
+ if ( cpu_has_xsaves )
+ {
+ if ( !(v->arch.xsave_area->xsave_hdr.xcomp_bv &
+ XSTATE_COMPACTION_ENABLED) )
+ v->arch.xsave_area->xsave_hdr.xcomp_bv = get_xcr0() |
+ XSTATE_COMPACTION_ENABLED;
+ xrstors(lmask, hmask, ptr);
+ }
+ else
+ asm volatile ( "1: .byte 0x48,0x0f,0xae,0x2f\n"
+ ".section .fixup,\"ax\" \n"
+ "2: mov %5,%%ecx \n"
+ " xor %1,%1 \n"
+ " rep stosb \n"
+ " lea %2,%0 \n"
+ " mov %3,%1 \n"
+ " jmp 1b \n"
+ ".previous \n"
+ _ASM_EXTABLE(1b, 2b)
+ : "+&D" (ptr), "+&a" (lmask)
+ : "m" (*ptr), "g" (lmask), "d" (hmask),
+ "m" (xsave_cntxt_size)
+ : "ecx" );
break;
case 4: case 2:
- asm volatile ( "1: .byte 0x0f,0xae,0x2f\n"
- ".section .fixup,\"ax\" \n"
- "2: mov %5,%%ecx \n"
- " xor %1,%1 \n"
- " rep stosb \n"
- " lea %2,%0 \n"
- " mov %3,%1 \n"
- " jmp 1b \n"
- ".previous \n"
- _ASM_EXTABLE(1b, 2b)
- : "+&D" (ptr), "+&a" (lmask)
- : "m" (*ptr), "g" (lmask), "d" (hmask),
- "m" (xsave_cntxt_size)
- : "ecx" );
+ if ( cpu_has_xsaves )
+ {
+ if ( !(v->arch.xsave_area->xsave_hdr.xcomp_bv &
+ XSTATE_COMPACTION_ENABLED) )
+ v->arch.xsave_area->xsave_hdr.xcomp_bv = get_xcr0() |
+ XSTATE_COMPACTION_ENABLED;
+ xrstors(lmask, hmask, ptr);
+ }
+ else
+ asm volatile ( "1: .byte 0x48,0x0f,0xae,0x2f\n"
+ ".section .fixup,\"ax\" \n"
+ "2: mov %5,%%ecx \n"
+ " xor %1,%1 \n"
+ " rep stosb \n"
+ " lea %2,%0 \n"
+ " mov %3,%1 \n"
+ " jmp 1b \n"
+ ".previous \n"
+ _ASM_EXTABLE(1b, 2b)
+ : "+&D" (ptr), "+&a" (lmask)
+ : "m" (*ptr), "g" (lmask), "d" (hmask),
+ "m" (xsave_cntxt_size)
+ : "ecx" );
break;
}
}
diff --git a/xen/include/asm-x86/xstate.h b/xen/include/asm-x86/xstate.h
index 59c7156..d03d824 100644
--- a/xen/include/asm-x86/xstate.h
+++ b/xen/include/asm-x86/xstate.h
@@ -72,7 +72,8 @@ struct __packed __attribute__((aligned (64))) xsave_struct
struct {
u64 xstate_bv;
- u64 reserved[7];
+ u64 xcomp_bv;
+ u64 reserved[6];
} xsave_hdr; /* The 64-byte header */
struct { char x[XSTATE_YMM_SIZE]; } ymm; /* YMM */
--
1.9.1
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