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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH V1 1/2] x86/altp2m: Add hypercall to set a range of sve bits
On Tue, Nov 5, 2019 at 5:43 AM Alexandru Stefan ISAILA
<aisaila@xxxxxxxxxxxxxxx> wrote:
>
> By default the sve bits are not set.
> This patch adds a new hypercall, xc_altp2m_set_supress_ve_multi(),
> to set a range of sve bits.
> The core function, p2m_set_suppress_ve_multi(), does not brake in case
> of a error and it is doing a best effort for setting the bits in the
> given range. A check for continuation is made in order to have
> preemption on big ranges.
>
> Signed-off-by: Alexandru Isaila <aisaila@xxxxxxxxxxxxxxx>
> ---
> tools/libxc/include/xenctrl.h | 3 ++
> tools/libxc/xc_altp2m.c | 25 ++++++++++++++
> xen/arch/x86/hvm/hvm.c | 28 +++++++++++++--
> xen/arch/x86/mm/p2m.c | 61 +++++++++++++++++++++++++++++++++
> xen/include/public/hvm/hvm_op.h | 4 ++-
> xen/include/xen/mem_access.h | 3 ++
> 6 files changed, 121 insertions(+), 3 deletions(-)
>
> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> index f4431687b3..21b644f459 100644
> --- a/tools/libxc/include/xenctrl.h
> +++ b/tools/libxc/include/xenctrl.h
> @@ -1923,6 +1923,9 @@ int xc_altp2m_switch_to_view(xc_interface *handle,
> uint32_t domid,
> uint16_t view_id);
> int xc_altp2m_set_suppress_ve(xc_interface *handle, uint32_t domid,
> uint16_t view_id, xen_pfn_t gfn, bool sve);
> +int xc_altp2m_set_supress_ve_multi(xc_interface *handle, uint32_t domid,
> + uint16_t view_id, xen_pfn_t start_gfn,
> + uint32_t nr, bool sve);
> int xc_altp2m_get_suppress_ve(xc_interface *handle, uint32_t domid,
> uint16_t view_id, xen_pfn_t gfn, bool *sve);
> int xc_altp2m_set_mem_access(xc_interface *handle, uint32_t domid,
> diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
> index 09dad0355e..6605d9abbe 100644
> --- a/tools/libxc/xc_altp2m.c
> +++ b/tools/libxc/xc_altp2m.c
> @@ -234,6 +234,31 @@ int xc_altp2m_set_suppress_ve(xc_interface *handle,
> uint32_t domid,
> return rc;
> }
>
> +int xc_altp2m_set_supress_ve_multi(xc_interface *handle, uint32_t domid,
> + uint16_t view_id, xen_pfn_t start_gfn,
> + uint32_t nr, bool sve)
> +{
> + int rc;
> + DECLARE_HYPERCALL_BUFFER(xen_hvm_altp2m_op_t, arg);
> +
> + arg = xc_hypercall_buffer_alloc(handle, arg, sizeof(*arg));
> + if ( arg == NULL )
> + return -1;
> +
> + arg->version = HVMOP_ALTP2M_INTERFACE_VERSION;
> + arg->cmd = HVMOP_altp2m_set_suppress_ve_multi;
> + arg->domain = domid;
> + arg->u.suppress_ve.view = view_id;
> + arg->u.suppress_ve.gfn = start_gfn;
> + arg->u.suppress_ve.suppress_ve = sve;
> + arg->u.suppress_ve.nr = nr;
> +
> + rc = xencall2(handle->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
> + HYPERCALL_BUFFER_AS_ARG(arg));
> + xc_hypercall_buffer_free(handle, arg);
> + return rc;
> +}
> +
> int xc_altp2m_set_mem_access(xc_interface *handle, uint32_t domid,
> uint16_t view_id, xen_pfn_t gfn,
> xenmem_access_t access)
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 06a7b40107..d3d9f8c30f 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -4535,6 +4535,7 @@ static int do_altp2m_op(
> case HVMOP_altp2m_destroy_p2m:
> case HVMOP_altp2m_switch_p2m:
> case HVMOP_altp2m_set_suppress_ve:
> + case HVMOP_altp2m_set_suppress_ve_multi:
> case HVMOP_altp2m_get_suppress_ve:
> case HVMOP_altp2m_set_mem_access:
> case HVMOP_altp2m_set_mem_access_multi:
> @@ -4681,7 +4682,7 @@ static int do_altp2m_op(
> break;
>
> case HVMOP_altp2m_set_suppress_ve:
> - if ( a.u.suppress_ve.pad1 || a.u.suppress_ve.pad2 )
> + if ( a.u.suppress_ve.pad1 )
> rc = -EINVAL;
> else
> {
> @@ -4693,8 +4694,31 @@ static int do_altp2m_op(
> }
> break;
>
> + case HVMOP_altp2m_set_suppress_ve_multi:
> + if ( a.u.suppress_ve.pad1 || !a.u.suppress_ve.nr )
> + rc = -EINVAL;
> + else
> + {
> + rc = p2m_set_suppress_ve_multi(d, a.u.suppress_ve.gfn,
> + a.u.suppress_ve.nr,
> + a.u.suppress_ve.suppress_ve,
> + a.u.suppress_ve.view);
I have to say I'm not a fan of stuffing the current gfn progress into
rc, perhaps a separate pointer being passed in for storing that and
returning -ERESTART would be cleaner.
> + if ( rc > 0 )
> + {
> + a.u.suppress_ve.gfn = rc;
There had been discussion in the past whether its acceptable to
overwrite fields that were passed in like this. This may not be the
expected behavior. For the mem_sharing side at least we have
introduced an "opaque" field in the structure to store that
continuation value (see
https://xenbits.xen.org/gitweb/?p=xen.git;a=blob;f=xen/include/public/memory.h;h=cfdda6e2a87ed30bed590034d8d717674abfbc79;hb=HEAD#l524).
> + rc = -ERESTART;
> +
> + if ( __copy_field_to_guest(guest_handle_cast(arg,
> + xen_hvm_altp2m_op_t),
> + &a, u.suppress_ve.gfn) )
> + rc = -EFAULT;
> + }
> + }
> + break;
> +
> case HVMOP_altp2m_get_suppress_ve:
> - if ( a.u.suppress_ve.pad1 || a.u.suppress_ve.pad2 )
> + if ( a.u.suppress_ve.pad1 )
> rc = -EINVAL;
> else
> {
> diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
> index e5e4349dea..b2e63e75ff 100644
> --- a/xen/arch/x86/mm/p2m.c
> +++ b/xen/arch/x86/mm/p2m.c
> @@ -3054,6 +3054,67 @@ out:
> return rc;
> }
>
> +/*
> + * Set/clear the #VE suppress bit for multiple pages. Only available on VMX.
> + */
> +long p2m_set_suppress_ve_multi(struct domain *d, uint32_t start, uint32_t nr,
> + bool suppress_ve, unsigned int altp2m_idx)
> +{
> + struct p2m_domain *host_p2m = p2m_get_hostp2m(d);
> + struct p2m_domain *ap2m = NULL;
> + struct p2m_domain *p2m;
> + long rc = 0;
> +
> + if ( altp2m_idx > 0 )
> + {
> + if ( altp2m_idx >= MAX_ALTP2M ||
> + d->arch.altp2m_eptp[altp2m_idx] == mfn_x(INVALID_MFN) )
> + return -EINVAL;
> +
> + p2m = ap2m = d->arch.altp2m_p2m[altp2m_idx];
> + }
> + else
> + p2m = host_p2m;
> +
> + p2m_lock(host_p2m);
> +
> + if ( ap2m )
> + p2m_lock(ap2m);
> +
> +
> + while ( start < nr )
> + {
> + p2m_access_t a;
> + p2m_type_t t;
> + mfn_t mfn;
> +
> + rc = altp2m_get_effective_entry(p2m, _gfn(start), &mfn, &t, &a,
> AP2MGET_query);
> +
> + if ( rc )
> + a = p2m->default_access;
> +
> + rc = p2m->set_entry(p2m, _gfn(start), mfn, PAGE_ORDER_4K, t, a,
> suppress_ve);
> +
> + /* Try best effort for setting the whole range. */
> + if ( rc )
> + continue;
> +
> + /* Check for continuation if it's not the last iteration. */
> + if ( nr > ++start && hypercall_preempt_check() )
> + {
> + rc = start;
> + break;
> + }
> + }
> +
> + if ( ap2m )
> + p2m_unlock(ap2m);
> +
> + p2m_unlock(host_p2m);
> +
> + return rc;
> +}
> +
> int p2m_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
> unsigned int altp2m_idx)
> {
> diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
> index 353f8034d9..bccfc45a07 100644
> --- a/xen/include/public/hvm/hvm_op.h
> +++ b/xen/include/public/hvm/hvm_op.h
> @@ -42,7 +42,7 @@ struct xen_hvm_altp2m_suppress_ve {
> uint16_t view;
> uint8_t suppress_ve; /* Boolean type. */
> uint8_t pad1;
> - uint32_t pad2;
> + uint32_t nr;
> uint64_t gfn;
> };
>
> @@ -339,6 +339,8 @@ struct xen_hvm_altp2m_op {
> #define HVMOP_altp2m_vcpu_disable_notify 13
> /* Get the active vcpu p2m index */
> #define HVMOP_altp2m_get_p2m_idx 14
> +/* Set the "Supress #VE" bit for a range of pages */
> +#define HVMOP_altp2m_set_suppress_ve_multi 15
> domid_t domain;
> uint16_t pad1;
> uint32_t pad2;
> diff --git a/xen/include/xen/mem_access.h b/xen/include/xen/mem_access.h
> index e4d24502e0..0c776fc7f3 100644
> --- a/xen/include/xen/mem_access.h
> +++ b/xen/include/xen/mem_access.h
> @@ -75,6 +75,9 @@ long p2m_set_mem_access_multi(struct domain *d,
> int p2m_set_suppress_ve(struct domain *d, gfn_t gfn, bool suppress_ve,
> unsigned int altp2m_idx);
>
> +long p2m_set_suppress_ve_multi(struct domain *d, uint32_t start, uint32_t nr,
> + bool suppress_ve, unsigned int altp2m_idx);
> +
> int p2m_get_suppress_ve(struct domain *d, gfn_t gfn, bool *suppress_ve,
> unsigned int altp2m_idx);
>
> --
> 2.17.1
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