From 8e221b6db4477643fefc885a97ea9889ac733140 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Tue, 22 Jun 2010 16:23:37 -0700 Subject: x86: Avoid unnecessary __clear_user() and xrstor in signal handling fxsave/xsave doesn't touch all the bytes in the memory layout used by these instructions. Specifically SW reserved (bytes 464..511) fields in the fxsave frame and the reserved fields in the xsave header. To present a clean context for the signal handling, just clear these fields instead of clearing the complete fxsave/xsave memory layout, when we dump these registers directly to the user signal frame. Also avoid the call to second xrstor (which inits the state not passed in the signal frame) in restore_user_xstate() if all the state has already been restored by the first xrstor. These changes improve the performance of signal handling(by ~3-5% as measured by the lat_sig). Signed-off-by: Suresh Siddha LKML-Reference: <1277249017.2847.85.camel@sbs-t61.sc.intel.com> Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/xsave.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 2c4390c..30dfc81 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -59,6 +59,16 @@ static inline int fpu_xrstor_checking(struct fpu *fpu) static inline int xsave_user(struct xsave_struct __user *buf) { int err; + + /* + * Clear the xsave header first, so that reserved fields are + * initialized to zero. + */ + err = __clear_user(&buf->xsave_hdr, + sizeof(struct xsave_hdr_struct)); + if (unlikely(err)) + return -EFAULT; + __asm__ __volatile__("1: .byte " REX_PREFIX "0x0f,0xae,0x27\n" "2:\n" ".section .fixup,\"ax\"\n" -- cgit v1.1 From 29104e101d710dd152f807978884643a52eca8b7 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 19 Jul 2010 16:05:49 -0700 Subject: x86, xsave: Sync xsave memory layout with its header for user handling With xsaveopt, if a processor implementation discern that a processor state component is in its initialized state it may modify the corresponding bit in the xsave_hdr.xstate_bv as '0', with out modifying the corresponding memory layout. Hence wHile presenting the xstate information to the user, we always ensure that the memory layout of a feature will be in the init state if the corresponding header bit is zero. This ensures the consistency and avoids the condition of the user seeing some some stale state in the memory layout during signal handling, debugging etc. Signed-off-by: Suresh Siddha LKML-Reference: <20100719230205.351459480@sbs-t61.sc.intel.com> Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/xsave.h | 10 ++++++++++ 1 file changed, 10 insertions(+) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 2c4390c..0c72adc 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -111,6 +111,16 @@ static inline void xrstor_state(struct xsave_struct *fx, u64 mask) : "memory"); } +static inline void xsave_state(struct xsave_struct *fx, u64 mask) +{ + u32 lmask = mask; + u32 hmask = mask >> 32; + + asm volatile(".byte " REX_PREFIX "0x0f,0xae,0x27\n\t" + : : "D" (fx), "m" (*fx), "a" (lmask), "d" (hmask) + : "memory"); +} + static inline void fpu_xsave(struct fpu *fpu) { /* This, however, we can work around by forcing the compiler to select -- cgit v1.1 From 6bad06b768920e278c7cedfdda56a0b4c6a35ee9 Mon Sep 17 00:00:00 2001 From: Suresh Siddha Date: Mon, 19 Jul 2010 16:05:52 -0700 Subject: x86, xsave: Use xsaveopt in context-switch path when supported xsaveopt is a more optimized form of xsave specifically designed for the context switch usage. xsaveopt doesn't save the state that's not modified from the prior xrstor. And if a specific feature state gets modified to the init state, then xsaveopt just updates the header bit in the xsave memory layout without updating the corresponding memory layout. Signed-off-by: Suresh Siddha LKML-Reference: <20100719230205.604014179@sbs-t61.sc.intel.com> Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/xsave.h | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 0c72adc..ec86c5f 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -125,8 +125,11 @@ static inline void fpu_xsave(struct fpu *fpu) { /* This, however, we can work around by forcing the compiler to select an addressing mode that doesn't require extended registers. */ - __asm__ __volatile__(".byte " REX_PREFIX "0x0f,0xae,0x27" - : : "D" (&(fpu->state->xsave)), - "a" (-1), "d"(-1) : "memory"); + alternative_input( + ".byte " REX_PREFIX "0x0f,0xae,0x27", + ".byte " REX_PREFIX "0x0f,0xae,0x37", + X86_FEATURE_XSAVEOPT, + [fx] "D" (&fpu->state->xsave), "a" (-1), "d" (-1) : + "memory"); } #endif -- cgit v1.1 From 7aa2b5f8ec60505160df1c25398e8286c8432689 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Tue, 20 Jul 2010 20:50:48 +0200 Subject: x86, xsave: Do not include asm/i387.h in asm/xsave.h MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit There are no dependencies to asm/i387.h. Instead, if including only xsave.h the following error occurs: .../arch/x86/include/asm/i387.h:110: error: ‘XSTATE_FP’ undeclared (first use in this function) .../arch/x86/include/asm/i387.h:110: error: (Each undeclared identifier is reported only once .../arch/x86/include/asm/i387.h:110: error: for each function it appears in.) This patch fixes this. Signed-off-by: Robert Richter LKML-Reference: <1279651857-24639-2-git-send-email-robert.richter@amd.com> Acked-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/xsave.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index ec86c5f..94d5f84 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -3,7 +3,6 @@ #include #include -#include #define XSTATE_FP 0x1 #define XSTATE_SSE 0x2 -- cgit v1.1 From 0e49bf66d2ca649b167428adddbbbe9d9bd4894c Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Wed, 21 Jul 2010 19:03:52 +0200 Subject: x86, xsave: Separate fpu and xsave initialization As xsave also supports other than fpu features, it should be initialized independently of the fpu. This patch moves this out of fpu initialization. There is also a lot of cross referencing between fpu and xsave code. This patch reduces this by making xsave_cntxt_init() and init_thread_xstate() static functions. The patch moves the cpu_has_xsave check at the beginning of xsave_init(). All other checks may removed then. Signed-off-by: Robert Richter LKML-Reference: <1279731838-1522-2-git-send-email-robert.richter@amd.com> Acked-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/xsave.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 94d5f84..4d3b5d1 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -28,7 +28,6 @@ extern u64 pcntxt_mask; extern struct xsave_struct *init_xstate_buf; extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS]; -extern void xsave_cntxt_init(void); extern void xsave_init(void); extern void update_regset_xstate_info(unsigned int size, u64 xstate_mask); extern int init_fpu(struct task_struct *child); -- cgit v1.1 From ee813d53a8e980a3a28318efb8935d45723f5211 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Wed, 21 Jul 2010 19:03:54 +0200 Subject: x86, xsave: Check cpuid level for XSTATE_CPUID (0x0d) The patch introduces the XSTATE_CPUID macro and adds a check that tests if XSTATE_CPUID exists. Signed-off-by: Robert Richter LKML-Reference: <1279731838-1522-4-git-send-email-robert.richter@amd.com> Acked-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/xsave.h | 2 ++ 1 file changed, 2 insertions(+) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 4d3b5d1..d1b5f3a 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -4,6 +4,8 @@ #include #include +#define XSTATE_CPUID 0x0000000d + #define XSTATE_FP 0x1 #define XSTATE_SSE 0x2 #define XSTATE_YMM 0x4 -- cgit v1.1 From 45c2d7f46211a0b1f6b425c59575c53145afc4b4 Mon Sep 17 00:00:00 2001 From: Robert Richter Date: Wed, 21 Jul 2010 19:03:55 +0200 Subject: x86, xsave: Make init_xstate_buf static The pointer is only used in xsave.c. Making it static. Signed-off-by: Robert Richter LKML-Reference: <1279731838-1522-5-git-send-email-robert.richter@amd.com> Acked-by: Suresh Siddha Signed-off-by: H. Peter Anvin --- arch/x86/include/asm/xsave.h | 1 - 1 file changed, 1 deletion(-) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index d1b5f3a..0ae6b99 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -27,7 +27,6 @@ extern unsigned int xstate_size; extern u64 pcntxt_mask; -extern struct xsave_struct *init_xstate_buf; extern u64 xstate_fx_sw_bytes[USER_XSTATE_FX_SW_WORDS]; extern void xsave_init(void); -- cgit v1.1 From 5ee481da7b62a992b91f958bf26aaaa92354c170 Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Mon, 17 May 2010 17:22:23 +0800 Subject: x86: Export FPU API for KVM use Also add some constants. Signed-off-by: Sheng Yang Signed-off-by: Avi Kivity --- arch/x86/include/asm/xsave.h | 3 +++ 1 file changed, 3 insertions(+) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 2c4390c..29ee4e4 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -13,6 +13,9 @@ #define FXSAVE_SIZE 512 +#define XSTATE_YMM_SIZE 256 +#define XSTATE_YMM_OFFSET (512 + 64) + /* * These are the features that the OS can handle currently. */ -- cgit v1.1 From 2d5b5a665508c60577c1088e0405850a965b6795 Mon Sep 17 00:00:00 2001 From: Sheng Yang Date: Sun, 13 Jun 2010 17:29:39 +0800 Subject: KVM: x86: XSAVE/XRSTOR live migration support This patch enable save/restore of xsave state. Signed-off-by: Sheng Yang Signed-off-by: Marcelo Tosatti --- arch/x86/include/asm/xsave.h | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) (limited to 'arch/x86/include/asm/xsave.h') diff --git a/arch/x86/include/asm/xsave.h b/arch/x86/include/asm/xsave.h index 29ee4e4..32c3666 100644 --- a/arch/x86/include/asm/xsave.h +++ b/arch/x86/include/asm/xsave.h @@ -13,8 +13,11 @@ #define FXSAVE_SIZE 512 -#define XSTATE_YMM_SIZE 256 -#define XSTATE_YMM_OFFSET (512 + 64) +#define XSAVE_HDR_SIZE 64 +#define XSAVE_HDR_OFFSET FXSAVE_SIZE + +#define XSAVE_YMM_SIZE 256 +#define XSAVE_YMM_OFFSET (XSAVE_HDR_SIZE + XSAVE_HDR_OFFSET) /* * These are the features that the OS can handle currently. -- cgit v1.1