From: Shuai Ruan Date: Tue, 29 Mar 2016 15:15:57 +0000 (+0200) Subject: x86/xsaves: calculate comp_offsets[] based on xcomp_bv X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~1478 X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks://%22%22/%22http:/www.example.com/cgi/%22https:/%22bookmarks:/%22%22?a=commitdiff_plain;h=9979547be5875437abae58401093279113258b18;p=xen.git x86/xsaves: calculate comp_offsets[] based on xcomp_bv Previous patch using all available features calculate comp_offsets. This is wrong.This patch fix this bug by calculating the comp_offset based on xcomp_bv of current guest. Also, the comp_offset should take alignment into consideration. Reported-by: Jan Beulich Signed-off-by: Shuai Ruan Reviewed-by: Jan Beulich --- diff --git a/xen/arch/x86/xstate.c b/xen/arch/x86/xstate.c index 78cbfbb745..6d98f56f40 100644 --- a/xen/arch/x86/xstate.c +++ b/xen/arch/x86/xstate.c @@ -26,8 +26,8 @@ u64 __read_mostly xfeature_mask; static unsigned int *__read_mostly xstate_offsets; unsigned int *__read_mostly xstate_sizes; +static u64 __read_mostly xstate_align; static unsigned int __read_mostly xstate_features; -static unsigned int __read_mostly xstate_comp_offsets[sizeof(xfeature_mask)*8]; static uint32_t __read_mostly mxcsr_mask = 0x0000ffbf; @@ -94,7 +94,7 @@ static bool_t xsave_area_compressed(const struct xsave_struct *xsave_area) static int setup_xstate_features(bool_t bsp) { - unsigned int leaf, tmp, eax, ebx; + unsigned int leaf, eax, ebx, ecx, edx; if ( bsp ) { @@ -111,57 +111,71 @@ static int setup_xstate_features(bool_t bsp) for ( leaf = 2; leaf < xstate_features; leaf++ ) { if ( bsp ) + { cpuid_count(XSTATE_CPUID, leaf, &xstate_sizes[leaf], - &xstate_offsets[leaf], &tmp, &tmp); + &xstate_offsets[leaf], &ecx, &edx); + if ( ecx & XSTATE_ALIGN64 ) + __set_bit(leaf, &xstate_align); + } else { cpuid_count(XSTATE_CPUID, leaf, &eax, - &ebx, &tmp, &tmp); + &ebx, &ecx, &edx); BUG_ON(eax != xstate_sizes[leaf]); BUG_ON(ebx != xstate_offsets[leaf]); + BUG_ON(!(ecx & XSTATE_ALIGN64) != !test_bit(leaf, &xstate_align)); } } return 0; } -static void __init setup_xstate_comp(void) +static void setup_xstate_comp(uint16_t *comp_offsets, + const uint64_t xcomp_bv) { unsigned int i; + unsigned int offset; /* * The FP xstates and SSE xstates are legacy states. They are always * in the fixed offsets in the xsave area in either compacted form * or standard form. */ - xstate_comp_offsets[0] = 0; - xstate_comp_offsets[1] = XSAVE_SSE_OFFSET; + comp_offsets[0] = 0; + comp_offsets[1] = XSAVE_SSE_OFFSET; - xstate_comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE; + comp_offsets[2] = FXSAVE_SIZE + XSAVE_HDR_SIZE; - for ( i = 3; i < xstate_features; i++ ) + offset = comp_offsets[2]; + for ( i = 2; i < xstate_features; i++ ) { - xstate_comp_offsets[i] = xstate_comp_offsets[i - 1] + - (((1ul << i) & xfeature_mask) - ? xstate_sizes[i - 1] : 0); - ASSERT(xstate_comp_offsets[i] + xstate_sizes[i] <= xsave_cntxt_size); + if ( (1ul << i) & xcomp_bv ) + { + if ( test_bit(i, &xstate_align) ) + offset = ROUNDUP(offset, 64); + comp_offsets[i] = offset; + offset += xstate_sizes[i]; + } } + ASSERT(offset <= xsave_cntxt_size); } static void *get_xsave_addr(struct xsave_struct *xsave, - unsigned int xfeature_idx) + const uint16_t *comp_offsets, + unsigned int xfeature_idx) { if ( !((1ul << xfeature_idx) & xsave->xsave_hdr.xstate_bv) ) return NULL; - return (void *)xsave + (xsave_area_compressed(xsave) - ? xstate_comp_offsets - : xstate_offsets)[xfeature_idx]; + return (void *)xsave + (xsave_area_compressed(xsave) ? + comp_offsets[xfeature_idx] : + xstate_offsets[xfeature_idx]); } void expand_xsave_states(struct vcpu *v, void *dest, unsigned int size) { struct xsave_struct *xsave = v->arch.xsave_area; + uint16_t comp_offsets[sizeof(xfeature_mask)*8]; u64 xstate_bv = xsave->xsave_hdr.xstate_bv; u64 valid; @@ -172,6 +186,8 @@ void expand_xsave_states(struct vcpu *v, void *dest, unsigned int size) } ASSERT(xsave_area_compressed(xsave)); + setup_xstate_comp(comp_offsets, xsave->xsave_hdr.xcomp_bv); + /* * Copy legacy XSAVE area and XSAVE hdr area. */ @@ -188,7 +204,7 @@ void expand_xsave_states(struct vcpu *v, void *dest, unsigned int size) { u64 feature = valid & -valid; unsigned int index = fls(feature) - 1; - const void *src = get_xsave_addr(xsave, index); + const void *src = get_xsave_addr(xsave, comp_offsets, index); if ( src ) { @@ -203,6 +219,7 @@ void expand_xsave_states(struct vcpu *v, void *dest, unsigned int size) void compress_xsave_states(struct vcpu *v, const void *src, unsigned int size) { struct xsave_struct *xsave = v->arch.xsave_area; + uint16_t comp_offsets[sizeof(xfeature_mask)*8]; u64 xstate_bv = ((const struct xsave_struct *)src)->xsave_hdr.xstate_bv; u64 valid; @@ -223,6 +240,8 @@ void compress_xsave_states(struct vcpu *v, const void *src, unsigned int size) xsave->xsave_hdr.xstate_bv = xstate_bv; xsave->xsave_hdr.xcomp_bv = v->arch.xcr0_accum | XSTATE_COMPACTION_ENABLED; + setup_xstate_comp(comp_offsets, xsave->xsave_hdr.xcomp_bv); + /* * Copy each region from the non-compacted offset to the * possibly compacted offset. @@ -232,7 +251,7 @@ void compress_xsave_states(struct vcpu *v, const void *src, unsigned int size) { u64 feature = valid & -valid; unsigned int index = fls(feature) - 1; - void *dest = get_xsave_addr(xsave, index); + void *dest = get_xsave_addr(xsave, comp_offsets, index); if ( dest ) { @@ -564,8 +583,6 @@ void xstate_init(struct cpuinfo_x86 *c) if ( setup_xstate_features(bsp) && bsp ) BUG(); - if ( bsp && (cpu_has_xsaves || cpu_has_xsavec) ) - setup_xstate_comp(); } static bool_t valid_xcr0(u64 xcr0) diff --git a/xen/include/asm-x86/xstate.h b/xen/include/asm-x86/xstate.h index c28cea5971..a488688960 100644 --- a/xen/include/asm-x86/xstate.h +++ b/xen/include/asm-x86/xstate.h @@ -46,6 +46,8 @@ #define XSTATE_LAZY (XSTATE_ALL & ~XSTATE_NONLAZY) #define XSTATE_COMPACTION_ENABLED (1ULL << 63) +#define XSTATE_ALIGN64 (1U << 1) + extern u64 xfeature_mask; extern unsigned int *xstate_sizes;