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Re: [PATCH v8 05/12] arm/sve: save/restore SVE context switch


  • To: Luca Fancellu <Luca.Fancellu@xxxxxxx>
  • From: Bertrand Marquis <Bertrand.Marquis@xxxxxxx>
  • Date: Thu, 1 Jun 2023 10:17:11 +0000
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  • Cc: Xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxxx>, Wei Chen <Wei.Chen@xxxxxxx>, Stefano Stabellini <sstabellini@xxxxxxxxxx>, Julien Grall <julien@xxxxxxx>, Volodymyr Babchuk <Volodymyr_Babchuk@xxxxxxxx>
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  • Thread-topic: [PATCH v8 05/12] arm/sve: save/restore SVE context switch

Hi Luca,

> On 31 May 2023, at 09:24, Luca Fancellu <Luca.Fancellu@xxxxxxx> wrote:
> 
> Save/restore context switch for SVE, allocate memory to contain
> the Z0-31 registers whose length is maximum 2048 bits each and
> FFR who can be maximum 256 bits, the allocated memory depends on
> how many bits is the vector length for the domain and how many bits
> are supported by the platform.
> 
> Save P0-15 whose length is maximum 256 bits each, in this case the
> memory used is from the fpregs field in struct vfp_state,
> because V0-31 are part of Z0-31 and this space would have been
> unused for SVE domain otherwise.
> 
> Create zcr_el{1,2} fields in arch_vcpu, initialise zcr_el2 on vcpu
> creation given the requested vector length and restore it on
> context switch, save/restore ZCR_EL1 value as well.
> 
> List import macros from Linux in README.LinuxPrimitives.
> 
> Signed-off-by: Luca Fancellu <luca.fancellu@xxxxxxx>

Reviewed-by: Bertrand Marquis <bertrand.marquis@xxxxxxx>

Cheers
Bertrand

> ---
> Changes from v7:
> - Fixed comments for sve_context_init and sve_context_free,
>   protect arch.vfp.sve_zreg_ctx_end, arch.zcr_el1, arch.zcr_el2
>   with ifdefs. (Julien)
> - Given the changes, dropped Bertrand's R-by
> Changes from v6:
> - Add comment for explain why sve_save/sve_load are different from
>   Linux, add macros in xen/arch/arm/README.LinuxPrimitives (Julien)
> - Add comments in sve_context_init and sve_context_free, handle the
>   case where sve_zreg_ctx_end is NULL, move setting of v->arch.zcr_el2
>   in sve_context_init (Julien)
> - remove stubs for sve_context_* and sve_save_* and rely on compiler
>   DCE (Jan)
> - Add comments for sve_save_ctx/sve_load_ctx (Julien)
> Changes from v5:
> - use XFREE instead of xfree, keep the headers (Julien)
> - Avoid math computation for every save/restore, store the computation
>   in struct vfp_state once (Bertrand)
> - protect access to v->domain->arch.sve_vl inside arch_vcpu_create now
>   that sve_vl is available only on arm64
> Changes from v4:
> - No changes
> Changes from v3:
> - don't use fixed len types when not needed (Jan)
> - now VL is an encoded value, decode it before using.
> Changes from v2:
> - No changes
> Changes from v1:
> - No changes
> Changes from RFC:
> - Moved zcr_el2 field introduction in this patch, restore its
>   content inside sve_restore_state function. (Julien)
> ---
> xen/arch/arm/README.LinuxPrimitives      |   4 +-
> xen/arch/arm/arm64/sve-asm.S             | 147 +++++++++++++++++++++++
> xen/arch/arm/arm64/sve.c                 |  91 ++++++++++++++
> xen/arch/arm/arm64/vfp.c                 |  79 ++++++------
> xen/arch/arm/domain.c                    |   6 +
> xen/arch/arm/include/asm/arm64/sve.h     |   4 +
> xen/arch/arm/include/asm/arm64/sysregs.h |   3 +
> xen/arch/arm/include/asm/arm64/vfp.h     |  16 +++
> xen/arch/arm/include/asm/domain.h        |   5 +
> 9 files changed, 320 insertions(+), 35 deletions(-)
> 
> diff --git a/xen/arch/arm/README.LinuxPrimitives 
> b/xen/arch/arm/README.LinuxPrimitives
> index 76c8df29e416..301c0271bbe4 100644
> --- a/xen/arch/arm/README.LinuxPrimitives
> +++ b/xen/arch/arm/README.LinuxPrimitives
> @@ -69,7 +69,9 @@ SVE assembly macro: last sync @ v6.3.0 (last commit: 
> 457391b03803)
> linux/arch/arm64/include/asm/fpsimdmacros.h   
> xen/arch/arm/include/asm/arm64/sve-asm.S
> 
> The following macros were taken from Linux:
> -    _check_general_reg, _check_num, _sve_rdvl
> +    _check_general_reg, _check_num, _sve_rdvl, __for, _for, _sve_check_zreg,
> +    _sve_check_preg, _sve_str_v, _sve_ldr_v, _sve_str_p, _sve_ldr_p, 
> _sve_rdffr,
> +    _sve_wrffr
> 
> =====================================================================
> arm32
> diff --git a/xen/arch/arm/arm64/sve-asm.S b/xen/arch/arm/arm64/sve-asm.S
> index 4d1549344733..59dbefbbb252 100644
> --- a/xen/arch/arm/arm64/sve-asm.S
> +++ b/xen/arch/arm/arm64/sve-asm.S
> @@ -17,6 +17,18 @@
>     .endif
> .endm
> 
> +.macro _sve_check_zreg znr
> +    .if (\znr) < 0 || (\znr) > 31
> +        .error "Bad Scalable Vector Extension vector register number \znr."
> +    .endif
> +.endm
> +
> +.macro _sve_check_preg pnr
> +    .if (\pnr) < 0 || (\pnr) > 15
> +        .error "Bad Scalable Vector Extension predicate register number 
> \pnr."
> +    .endif
> +.endm
> +
> .macro _check_num n, min, max
>     .if (\n) < (\min) || (\n) > (\max)
>         .error "Number \n out of range [\min,\max]"
> @@ -26,6 +38,54 @@
> /* SVE instruction encodings for non-SVE-capable assemblers */
> /* (pre binutils 2.28, all kernel capable clang versions support SVE) */
> 
> +/* STR (vector): STR Z\nz, [X\nxbase, #\offset, MUL VL] */
> +.macro _sve_str_v nz, nxbase, offset=0
> +    _sve_check_zreg \nz
> +    _check_general_reg \nxbase
> +    _check_num (\offset), -0x100, 0xff
> +    .inst 0xe5804000                \
> +        | (\nz)                     \
> +        | ((\nxbase) << 5)          \
> +        | (((\offset) & 7) << 10)   \
> +        | (((\offset) & 0x1f8) << 13)
> +.endm
> +
> +/* LDR (vector): LDR Z\nz, [X\nxbase, #\offset, MUL VL] */
> +.macro _sve_ldr_v nz, nxbase, offset=0
> +    _sve_check_zreg \nz
> +    _check_general_reg \nxbase
> +    _check_num (\offset), -0x100, 0xff
> +    .inst 0x85804000                \
> +        | (\nz)                     \
> +        | ((\nxbase) << 5)          \
> +        | (((\offset) & 7) << 10)   \
> +        | (((\offset) & 0x1f8) << 13)
> +.endm
> +
> +/* STR (predicate): STR P\np, [X\nxbase, #\offset, MUL VL] */
> +.macro _sve_str_p np, nxbase, offset=0
> +    _sve_check_preg \np
> +    _check_general_reg \nxbase
> +    _check_num (\offset), -0x100, 0xff
> +    .inst 0xe5800000                \
> +        | (\np)                     \
> +        | ((\nxbase) << 5)          \
> +        | (((\offset) & 7) << 10)   \
> +        | (((\offset) & 0x1f8) << 13)
> +.endm
> +
> +/* LDR (predicate): LDR P\np, [X\nxbase, #\offset, MUL VL] */
> +.macro _sve_ldr_p np, nxbase, offset=0
> +    _sve_check_preg \np
> +    _check_general_reg \nxbase
> +    _check_num (\offset), -0x100, 0xff
> +    .inst 0x85800000                \
> +        | (\np)                     \
> +        | ((\nxbase) << 5)          \
> +        | (((\offset) & 7) << 10)   \
> +        | (((\offset) & 0x1f8) << 13)
> +.endm
> +
> /* RDVL X\nx, #\imm */
> .macro _sve_rdvl nx, imm
>     _check_general_reg \nx
> @@ -35,11 +95,98 @@
>         | (((\imm) & 0x3f) << 5)
> .endm
> 
> +/* RDFFR (unpredicated): RDFFR P\np.B */
> +.macro _sve_rdffr np
> +    _sve_check_preg \np
> +    .inst 0x2519f000                \
> +        | (\np)
> +.endm
> +
> +/* WRFFR P\np.B */
> +.macro _sve_wrffr np
> +    _sve_check_preg \np
> +    .inst 0x25289000                \
> +        | ((\np) << 5)
> +.endm
> +
> +.macro __for from:req, to:req
> +    .if (\from) == (\to)
> +        _for__body %\from
> +    .else
> +        __for %\from, %((\from) + ((\to) - (\from)) / 2)
> +        __for %((\from) + ((\to) - (\from)) / 2 + 1), %\to
> +    .endif
> +.endm
> +
> +.macro _for var:req, from:req, to:req, insn:vararg
> +    .macro _for__body \var:req
> +        .noaltmacro
> +        \insn
> +        .altmacro
> +    .endm
> +
> +    .altmacro
> +    __for \from, \to
> +    .noaltmacro
> +
> +    .purgem _for__body
> +.endm
> +
> +/*
> + * sve_save and sve_load are different from the Linux version because the
> + * buffers to save the context are different from Xen and for example Linux
> + * is using this macro to save/restore also fpsr and fpcr while we do it in C
> + */
> +
> +.macro sve_save nxzffrctx, nxpctx, save_ffr
> +    _for n, 0, 31, _sve_str_v \n, \nxzffrctx, \n - 32
> +    _for n, 0, 15, _sve_str_p \n, \nxpctx, \n
> +        cbz \save_ffr, 1f
> +        _sve_rdffr 0
> +        _sve_str_p 0, \nxzffrctx
> +        _sve_ldr_p 0, \nxpctx
> +        b 2f
> +1:
> +        str xzr, [x\nxzffrctx]      // Zero out FFR
> +2:
> +.endm
> +
> +.macro sve_load nxzffrctx, nxpctx, restore_ffr
> +    _for n, 0, 31, _sve_ldr_v \n, \nxzffrctx, \n - 32
> +        cbz \restore_ffr, 1f
> +        _sve_ldr_p 0, \nxzffrctx
> +        _sve_wrffr 0
> +1:
> +    _for n, 0, 15, _sve_ldr_p \n, \nxpctx, \n
> +.endm
> +
> /* Gets the current vector register size in bytes */
> GLOBAL(sve_get_hw_vl)
>     _sve_rdvl 0, 1
>     ret
> 
> +/*
> + * Save the SVE context
> + *
> + * x0 - pointer to buffer for Z0-31 + FFR
> + * x1 - pointer to buffer for P0-15
> + * x2 - Save FFR if non-zero
> + */
> +GLOBAL(sve_save_ctx)
> +    sve_save 0, 1, x2
> +    ret
> +
> +/*
> + * Load the SVE context
> + *
> + * x0 - pointer to buffer for Z0-31 + FFR
> + * x1 - pointer to buffer for P0-15
> + * x2 - Restore FFR if non-zero
> + */
> +GLOBAL(sve_load_ctx)
> +    sve_load 0, 1, x2
> +    ret
> +
> /*
>  * Local variables:
>  * mode: ASM
> diff --git a/xen/arch/arm/arm64/sve.c b/xen/arch/arm/arm64/sve.c
> index a9144e48ef6b..56d8f27ea26a 100644
> --- a/xen/arch/arm/arm64/sve.c
> +++ b/xen/arch/arm/arm64/sve.c
> @@ -5,6 +5,7 @@
>  * Copyright (C) 2022 ARM Ltd.
>  */
> 
> +#include <xen/sizes.h>
> #include <xen/types.h>
> #include <asm/arm64/sve.h>
> #include <asm/arm64/sysregs.h>
> @@ -14,6 +15,25 @@
> 
> extern unsigned int sve_get_hw_vl(void);
> 
> +/*
> + * Save the SVE context
> + *
> + * sve_ctx - pointer to buffer for Z0-31 + FFR
> + * pregs - pointer to buffer for P0-15
> + * save_ffr - Save FFR if non-zero
> + */
> +extern void sve_save_ctx(uint64_t *sve_ctx, uint64_t *pregs, int save_ffr);
> +
> +/*
> + * Load the SVE context
> + *
> + * sve_ctx - pointer to buffer for Z0-31 + FFR
> + * pregs - pointer to buffer for P0-15
> + * restore_ffr - Restore FFR if non-zero
> + */
> +extern void sve_load_ctx(uint64_t const *sve_ctx, uint64_t const *pregs,
> +                         int restore_ffr);
> +
> /* Takes a vector length in bits and returns the ZCR_ELx encoding */
> static inline register_t vl_to_zcr(unsigned int vl)
> {
> @@ -21,6 +41,21 @@ static inline register_t vl_to_zcr(unsigned int vl)
>     return ((vl / SVE_VL_MULTIPLE_VAL) - 1U) & ZCR_ELx_LEN_MASK;
> }
> 
> +static inline unsigned int sve_zreg_ctx_size(unsigned int vl)
> +{
> +    /*
> +     * Z0-31 registers size in bytes is computed from VL that is in bits, so 
> VL
> +     * in bytes is VL/8.
> +     */
> +    return (vl / 8U) * 32U;
> +}
> +
> +static inline unsigned int sve_ffrreg_ctx_size(unsigned int vl)
> +{
> +    /* FFR register size is VL/8, which is in bytes (VL/8)/8 */
> +    return (vl / 64U);
> +}
> +
> register_t compute_max_zcr(void)
> {
>     register_t cptr_bits = get_default_cptr_flags();
> @@ -61,6 +96,62 @@ unsigned int get_sys_vl_len(void)
>             SVE_VL_MULTIPLE_VAL;
> }
> 
> +int sve_context_init(struct vcpu *v)
> +{
> +    unsigned int sve_vl_bits = sve_decode_vl(v->domain->arch.sve_vl);
> +    uint64_t *ctx = _xzalloc(sve_zreg_ctx_size(sve_vl_bits) +
> +                             sve_ffrreg_ctx_size(sve_vl_bits),
> +                             L1_CACHE_BYTES);
> +
> +    if ( !ctx )
> +        return -ENOMEM;
> +
> +    /*
> +     * Points to the end of Z0-Z31 memory, just before FFR memory, to be 
> kept in
> +     * sync with sve_context_free().
> +     */
> +    v->arch.vfp.sve_zreg_ctx_end = ctx +
> +        (sve_zreg_ctx_size(sve_vl_bits) / sizeof(uint64_t));
> +
> +    v->arch.zcr_el2 = vl_to_zcr(sve_vl_bits);
> +
> +    return 0;
> +}
> +
> +void sve_context_free(struct vcpu *v)
> +{
> +    unsigned int sve_vl_bits;
> +
> +    if ( v->arch.vfp.sve_zreg_ctx_end )
> +        return;
> +
> +    sve_vl_bits = sve_decode_vl(v->domain->arch.sve_vl);
> +
> +    /*
> +     * Currenly points to the end of Z0-Z31 memory which is not the start of
> +     * the buffer. To be kept in sync with the sve_context_init().
> +     */
> +    v->arch.vfp.sve_zreg_ctx_end -=
> +        (sve_zreg_ctx_size(sve_vl_bits) / sizeof(uint64_t));
> +
> +    XFREE(v->arch.vfp.sve_zreg_ctx_end);
> +}
> +
> +void sve_save_state(struct vcpu *v)
> +{
> +    v->arch.zcr_el1 = READ_SYSREG(ZCR_EL1);
> +
> +    sve_save_ctx(v->arch.vfp.sve_zreg_ctx_end, v->arch.vfp.fpregs, 1);
> +}
> +
> +void sve_restore_state(struct vcpu *v)
> +{
> +    WRITE_SYSREG(v->arch.zcr_el1, ZCR_EL1);
> +    WRITE_SYSREG(v->arch.zcr_el2, ZCR_EL2);
> +
> +    sve_load_ctx(v->arch.vfp.sve_zreg_ctx_end, v->arch.vfp.fpregs, 1);
> +}
> +
> /*
>  * Local variables:
>  * mode: C
> diff --git a/xen/arch/arm/arm64/vfp.c b/xen/arch/arm/arm64/vfp.c
> index 47885e76baae..2d0d7c2e6ddb 100644
> --- a/xen/arch/arm/arm64/vfp.c
> +++ b/xen/arch/arm/arm64/vfp.c
> @@ -2,29 +2,35 @@
> #include <asm/processor.h>
> #include <asm/cpufeature.h>
> #include <asm/vfp.h>
> +#include <asm/arm64/sve.h>
> 
> void vfp_save_state(struct vcpu *v)
> {
>     if ( !cpu_has_fp )
>         return;
> 
> -    asm volatile("stp q0, q1, [%1, #16 * 0]\n\t"
> -                 "stp q2, q3, [%1, #16 * 2]\n\t"
> -                 "stp q4, q5, [%1, #16 * 4]\n\t"
> -                 "stp q6, q7, [%1, #16 * 6]\n\t"
> -                 "stp q8, q9, [%1, #16 * 8]\n\t"
> -                 "stp q10, q11, [%1, #16 * 10]\n\t"
> -                 "stp q12, q13, [%1, #16 * 12]\n\t"
> -                 "stp q14, q15, [%1, #16 * 14]\n\t"
> -                 "stp q16, q17, [%1, #16 * 16]\n\t"
> -                 "stp q18, q19, [%1, #16 * 18]\n\t"
> -                 "stp q20, q21, [%1, #16 * 20]\n\t"
> -                 "stp q22, q23, [%1, #16 * 22]\n\t"
> -                 "stp q24, q25, [%1, #16 * 24]\n\t"
> -                 "stp q26, q27, [%1, #16 * 26]\n\t"
> -                 "stp q28, q29, [%1, #16 * 28]\n\t"
> -                 "stp q30, q31, [%1, #16 * 30]\n\t"
> -                 : "=Q" (*v->arch.vfp.fpregs) : "r" (v->arch.vfp.fpregs));
> +    if ( is_sve_domain(v->domain) )
> +        sve_save_state(v);
> +    else
> +    {
> +        asm volatile("stp q0, q1, [%1, #16 * 0]\n\t"
> +                     "stp q2, q3, [%1, #16 * 2]\n\t"
> +                     "stp q4, q5, [%1, #16 * 4]\n\t"
> +                     "stp q6, q7, [%1, #16 * 6]\n\t"
> +                     "stp q8, q9, [%1, #16 * 8]\n\t"
> +                     "stp q10, q11, [%1, #16 * 10]\n\t"
> +                     "stp q12, q13, [%1, #16 * 12]\n\t"
> +                     "stp q14, q15, [%1, #16 * 14]\n\t"
> +                     "stp q16, q17, [%1, #16 * 16]\n\t"
> +                     "stp q18, q19, [%1, #16 * 18]\n\t"
> +                     "stp q20, q21, [%1, #16 * 20]\n\t"
> +                     "stp q22, q23, [%1, #16 * 22]\n\t"
> +                     "stp q24, q25, [%1, #16 * 24]\n\t"
> +                     "stp q26, q27, [%1, #16 * 26]\n\t"
> +                     "stp q28, q29, [%1, #16 * 28]\n\t"
> +                     "stp q30, q31, [%1, #16 * 30]\n\t"
> +                     : "=Q" (*v->arch.vfp.fpregs) : "r" 
> (v->arch.vfp.fpregs));
> +    }
> 
>     v->arch.vfp.fpsr = READ_SYSREG(FPSR);
>     v->arch.vfp.fpcr = READ_SYSREG(FPCR);
> @@ -37,23 +43,28 @@ void vfp_restore_state(struct vcpu *v)
>     if ( !cpu_has_fp )
>         return;
> 
> -    asm volatile("ldp q0, q1, [%1, #16 * 0]\n\t"
> -                 "ldp q2, q3, [%1, #16 * 2]\n\t"
> -                 "ldp q4, q5, [%1, #16 * 4]\n\t"
> -                 "ldp q6, q7, [%1, #16 * 6]\n\t"
> -                 "ldp q8, q9, [%1, #16 * 8]\n\t"
> -                 "ldp q10, q11, [%1, #16 * 10]\n\t"
> -                 "ldp q12, q13, [%1, #16 * 12]\n\t"
> -                 "ldp q14, q15, [%1, #16 * 14]\n\t"
> -                 "ldp q16, q17, [%1, #16 * 16]\n\t"
> -                 "ldp q18, q19, [%1, #16 * 18]\n\t"
> -                 "ldp q20, q21, [%1, #16 * 20]\n\t"
> -                 "ldp q22, q23, [%1, #16 * 22]\n\t"
> -                 "ldp q24, q25, [%1, #16 * 24]\n\t"
> -                 "ldp q26, q27, [%1, #16 * 26]\n\t"
> -                 "ldp q28, q29, [%1, #16 * 28]\n\t"
> -                 "ldp q30, q31, [%1, #16 * 30]\n\t"
> -                 : : "Q" (*v->arch.vfp.fpregs), "r" (v->arch.vfp.fpregs));
> +    if ( is_sve_domain(v->domain) )
> +        sve_restore_state(v);
> +    else
> +    {
> +        asm volatile("ldp q0, q1, [%1, #16 * 0]\n\t"
> +                     "ldp q2, q3, [%1, #16 * 2]\n\t"
> +                     "ldp q4, q5, [%1, #16 * 4]\n\t"
> +                     "ldp q6, q7, [%1, #16 * 6]\n\t"
> +                     "ldp q8, q9, [%1, #16 * 8]\n\t"
> +                     "ldp q10, q11, [%1, #16 * 10]\n\t"
> +                     "ldp q12, q13, [%1, #16 * 12]\n\t"
> +                     "ldp q14, q15, [%1, #16 * 14]\n\t"
> +                     "ldp q16, q17, [%1, #16 * 16]\n\t"
> +                     "ldp q18, q19, [%1, #16 * 18]\n\t"
> +                     "ldp q20, q21, [%1, #16 * 20]\n\t"
> +                     "ldp q22, q23, [%1, #16 * 22]\n\t"
> +                     "ldp q24, q25, [%1, #16 * 24]\n\t"
> +                     "ldp q26, q27, [%1, #16 * 26]\n\t"
> +                     "ldp q28, q29, [%1, #16 * 28]\n\t"
> +                     "ldp q30, q31, [%1, #16 * 30]\n\t"
> +                     : : "Q" (*v->arch.vfp.fpregs), "r" 
> (v->arch.vfp.fpregs));
> +    }
> 
>     WRITE_SYSREG(v->arch.vfp.fpsr, FPSR);
>     WRITE_SYSREG(v->arch.vfp.fpcr, FPCR);
> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
> index 6c22551b0ed2..add9929b7943 100644
> --- a/xen/arch/arm/domain.c
> +++ b/xen/arch/arm/domain.c
> @@ -557,7 +557,11 @@ int arch_vcpu_create(struct vcpu *v)
> 
>     v->arch.cptr_el2 = get_default_cptr_flags();
>     if ( is_sve_domain(v->domain) )
> +    {
> +        if ( (rc = sve_context_init(v)) != 0 )
> +            goto fail;
>         v->arch.cptr_el2 &= ~HCPTR_CP(8);
> +    }
> 
>     v->arch.hcr_el2 = get_default_hcr_flags();
> 
> @@ -587,6 +591,8 @@ fail:
> 
> void arch_vcpu_destroy(struct vcpu *v)
> {
> +    if ( is_sve_domain(v->domain) )
> +        sve_context_free(v);
>     vcpu_timer_destroy(v);
>     vcpu_vgic_free(v);
>     free_xenheap_pages(v->arch.stack, STACK_ORDER);
> diff --git a/xen/arch/arm/include/asm/arm64/sve.h 
> b/xen/arch/arm/include/asm/arm64/sve.h
> index 4b63412727fc..65b46685d263 100644
> --- a/xen/arch/arm/include/asm/arm64/sve.h
> +++ b/xen/arch/arm/include/asm/arm64/sve.h
> @@ -22,6 +22,10 @@ static inline unsigned int sve_decode_vl(unsigned int 
> sve_vl)
> }
> 
> register_t compute_max_zcr(void);
> +int sve_context_init(struct vcpu *v);
> +void sve_context_free(struct vcpu *v);
> +void sve_save_state(struct vcpu *v);
> +void sve_restore_state(struct vcpu *v);
> 
> #ifdef CONFIG_ARM64_SVE
> 
> diff --git a/xen/arch/arm/include/asm/arm64/sysregs.h 
> b/xen/arch/arm/include/asm/arm64/sysregs.h
> index 4cabb9eb4d5e..3fdeb9d8cdef 100644
> --- a/xen/arch/arm/include/asm/arm64/sysregs.h
> +++ b/xen/arch/arm/include/asm/arm64/sysregs.h
> @@ -88,6 +88,9 @@
> #ifndef ID_AA64ISAR2_EL1
> #define ID_AA64ISAR2_EL1            S3_0_C0_C6_2
> #endif
> +#ifndef ZCR_EL1
> +#define ZCR_EL1                     S3_0_C1_C2_0
> +#endif
> 
> /* ID registers (imported from arm64/include/asm/sysreg.h in Linux) */
> 
> diff --git a/xen/arch/arm/include/asm/arm64/vfp.h 
> b/xen/arch/arm/include/asm/arm64/vfp.h
> index e6e8c363bc16..4b399ccbfb31 100644
> --- a/xen/arch/arm/include/asm/arm64/vfp.h
> +++ b/xen/arch/arm/include/asm/arm64/vfp.h
> @@ -6,7 +6,23 @@
> 
> struct vfp_state
> {
> +    /*
> +     * When SVE is enabled for the guest, fpregs memory will be used to
> +     * save/restore P0-P15 registers, otherwise it will be used for the 
> V0-V31
> +     * registers.
> +     */
>     uint64_t fpregs[64] __vfp_aligned;
> +
> +#ifdef CONFIG_ARM64_SVE
> +    /*
> +     * When SVE is enabled for the guest, sve_zreg_ctx_end points to memory
> +     * where Z0-Z31 registers and FFR can be saved/restored, it points at the
> +     * end of the Z0-Z31 space and at the beginning of the FFR space, it's 
> done
> +     * like that to ease the save/restore assembly operations.
> +     */
> +    uint64_t *sve_zreg_ctx_end;
> +#endif
> +
>     register_t fpcr;
>     register_t fpexc32_el2;
>     register_t fpsr;
> diff --git a/xen/arch/arm/include/asm/domain.h 
> b/xen/arch/arm/include/asm/domain.h
> index 331da0f3bcc3..99e798ffff68 100644
> --- a/xen/arch/arm/include/asm/domain.h
> +++ b/xen/arch/arm/include/asm/domain.h
> @@ -195,6 +195,11 @@ struct arch_vcpu
>     register_t tpidrro_el0;
> 
>     /* HYP configuration */
> +#ifdef CONFIG_ARM64_SVE
> +    register_t zcr_el1;
> +    register_t zcr_el2;
> +#endif
> +
>     register_t cptr_el2;
>     register_t hcr_el2;
>     register_t mdcr_el2;
> -- 
> 2.34.1
> 




 


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