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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH v4] x86/altp2m: Add a subop for obtaining the mem access of a page
On Mon, Sep 3, 2018 at 9:47 AM Adrian Pop <apop@xxxxxxxxxxxxxxx> wrote:
>
> Currently there is a subop for setting the memaccess of a page, but not
> for consulting it. The new HVMOP_altp2m_get_mem_access adds this
> functionality.
>
> Both altp2m get/set mem access functions use the struct
> xen_hvm_altp2m_mem_access which has now dropped the `set' part and has
> been renamed from xen_hvm_altp2m_set_mem_access.
>
> Signed-off-by: Adrian Pop <apop@xxxxxxxxxxxxxxx>
> ---
> Changes in v4:
> - don't break the stable interface
>
> Changes in v3:
> - remove the unrelated helper function
> - simplify the locking in p2m_get_mem_access
>
> Changes in v2:
> - use the _p2m_get_mem_access helper from p2m_get_mem_access
> - minor Arm adjustments
> - move out the addition of a memaccess helper function to a separate
> patch in the attempts of making the diff clearer
> ---
> tools/libxc/include/xenctrl.h | 3 +++
> tools/libxc/xc_altp2m.c | 33 +++++++++++++++++++++++++++++++++
> xen/arch/arm/mem_access.c | 8 ++++++--
> xen/arch/x86/hvm/hvm.c | 27 +++++++++++++++++++++++++++
> xen/arch/x86/mm/mem_access.c | 21 +++++++++++++++++++--
> xen/common/mem_access.c | 2 +-
> xen/include/public/hvm/hvm_op.h | 19 +++++++++++++++++++
> xen/include/public/xen-compat.h | 2 +-
> xen/include/xen/mem_access.h | 3 ++-
> 9 files changed, 111 insertions(+), 7 deletions(-)
>
> diff --git a/tools/libxc/include/xenctrl.h b/tools/libxc/include/xenctrl.h
> index c626984aba..ae298899fc 100644
> --- a/tools/libxc/include/xenctrl.h
> +++ b/tools/libxc/include/xenctrl.h
> @@ -1958,6 +1958,9 @@ int xc_altp2m_set_mem_access(xc_interface *handle,
> uint32_t domid,
> int xc_altp2m_set_mem_access_multi(xc_interface *handle, uint32_t domid,
> uint16_t view_id, uint8_t *access,
> uint64_t *gfns, uint32_t nr);
> +int xc_altp2m_get_mem_access(xc_interface *handle, uint32_t domid,
> + uint16_t view_id, xen_pfn_t gfn,
> + xenmem_access_t *access);
> int xc_altp2m_change_gfn(xc_interface *handle, uint32_t domid,
> uint16_t view_id, xen_pfn_t old_gfn,
> xen_pfn_t new_gfn);
> diff --git a/tools/libxc/xc_altp2m.c b/tools/libxc/xc_altp2m.c
> index ce4a1e4d60..53754ff6d3 100644
> --- a/tools/libxc/xc_altp2m.c
> +++ b/tools/libxc/xc_altp2m.c
> @@ -177,9 +177,15 @@ int xc_altp2m_set_mem_access(xc_interface *handle,
> uint32_t domid,
> arg->version = HVMOP_ALTP2M_INTERFACE_VERSION;
> arg->cmd = HVMOP_altp2m_set_mem_access;
> arg->domain = domid;
> +#if __XEN_INTERFACE_VERSION__ < 0x00040a00
> arg->u.set_mem_access.view = view_id;
> arg->u.set_mem_access.hvmmem_access = access;
> arg->u.set_mem_access.gfn = gfn;
> +#else /* __XEN_INTERFACE_VERSION__ >= 0x00040a00 */
> + arg->u.mem_access.view = view_id;
> + arg->u.mem_access.hvmmem_access = access;
> + arg->u.mem_access.gfn = gfn;
> +#endif
>
> rc = xencall2(handle->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
> HYPERCALL_BUFFER_AS_ARG(arg));
> @@ -254,3 +260,30 @@ int xc_altp2m_set_mem_access_multi(xc_interface *xch,
> uint32_t domid,
>
> return rc;
> }
> +
> +int xc_altp2m_get_mem_access(xc_interface *handle, uint32_t domid,
> + uint16_t view_id, xen_pfn_t gfn,
> + xenmem_access_t *access)
> +{
> + 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_get_mem_access;
> + arg->domain = domid;
> + arg->u.mem_access.view = view_id;
> + arg->u.mem_access.gfn = gfn;
> +
> + rc = xencall2(handle->xcall, __HYPERVISOR_hvm_op, HVMOP_altp2m,
> + HYPERCALL_BUFFER_AS_ARG(arg));
> +
> + if ( !rc )
> + *access = arg->u.mem_access.hvmmem_access;
> +
> + xc_hypercall_buffer_free(handle, arg);
> + return rc;
> +}
> diff --git a/xen/arch/arm/mem_access.c b/xen/arch/arm/mem_access.c
> index ba4ec780fd..178bc1a6c1 100644
> --- a/xen/arch/arm/mem_access.c
> +++ b/xen/arch/arm/mem_access.c
> @@ -236,7 +236,7 @@ bool p2m_mem_access_check(paddr_t gpa, vaddr_t gla, const
> struct npfec npfec)
> if ( !p2m->mem_access_enabled )
> return true;
>
> - rc = p2m_get_mem_access(v->domain, gaddr_to_gfn(gpa), &xma);
> + rc = p2m_get_mem_access(v->domain, gaddr_to_gfn(gpa), &xma, 0);
> if ( rc )
> return true;
>
> @@ -441,11 +441,15 @@ long p2m_set_mem_access_multi(struct domain *d,
> }
>
> int p2m_get_mem_access(struct domain *d, gfn_t gfn,
> - xenmem_access_t *access)
> + xenmem_access_t *access, unsigned int altp2m_idx)
> {
> int ret;
> struct p2m_domain *p2m = p2m_get_hostp2m(d);
>
> + /* altp2m is not yet implemented on Arm. The altp2m_idx should be 0. */
Just use ASSERT here.
> + if ( altp2m_idx )
> + return -EINVAL;
> +
> p2m_read_lock(p2m);
> ret = __p2m_get_mem_access(d, gfn, access);
> p2m_read_unlock(p2m);
> diff --git a/xen/arch/x86/hvm/hvm.c b/xen/arch/x86/hvm/hvm.c
> index 72c51faecb..460c9f7d4f 100644
> --- a/xen/arch/x86/hvm/hvm.c
> +++ b/xen/arch/x86/hvm/hvm.c
> @@ -4526,6 +4526,7 @@ static int do_altp2m_op(
> case HVMOP_altp2m_switch_p2m:
> case HVMOP_altp2m_set_mem_access:
> case HVMOP_altp2m_set_mem_access_multi:
> + case HVMOP_altp2m_get_mem_access:
> case HVMOP_altp2m_change_gfn:
> break;
>
> @@ -4642,12 +4643,21 @@ static int do_altp2m_op(
> break;
>
> case HVMOP_altp2m_set_mem_access:
> +#if __XEN_INTERFACE_VERSION__ < 0x00040a00
> if ( a.u.set_mem_access.pad )
> rc = -EINVAL;
> else
> rc = p2m_set_mem_access(d, _gfn(a.u.set_mem_access.gfn), 1, 0, 0,
> a.u.set_mem_access.hvmmem_access,
> a.u.set_mem_access.view);
> +#else /* __XEN_INTERFACE_VERSION__ >= 0x00040a00 */
> + if ( a.u.mem_access.pad )
> + rc = -EINVAL;
> + else
> + rc = p2m_set_mem_access(d, _gfn(a.u.mem_access.gfn), 1, 0, 0,
> + a.u.mem_access.hvmmem_access,
> + a.u.mem_access.view);
> +#endif
> break;
>
> case HVMOP_altp2m_set_mem_access_multi:
> @@ -4683,6 +4693,23 @@ static int do_altp2m_op(
> }
> break;
>
> + case HVMOP_altp2m_get_mem_access:
> + if ( a.u.mem_access.pad )
> + rc = -EINVAL;
> + else
> + {
> + xenmem_access_t access;
> +
> + rc = p2m_get_mem_access(d, _gfn(a.u.mem_access.gfn), &access,
> + a.u.mem_access.view);
> + if ( !rc )
> + {
> + a.u.mem_access.hvmmem_access = access;
> + rc = __copy_to_guest(arg, &a, 1) ? -EFAULT : 0;
> + }
> + }
> + break;
> +
> case HVMOP_altp2m_change_gfn:
> if ( a.u.change_gfn.pad1 || a.u.change_gfn.pad2 )
> rc = -EINVAL;
> diff --git a/xen/arch/x86/mm/mem_access.c b/xen/arch/x86/mm/mem_access.c
> index 84d260ebd8..78abdaed36 100644
> --- a/xen/arch/x86/mm/mem_access.c
> +++ b/xen/arch/x86/mm/mem_access.c
> @@ -469,9 +469,26 @@ long p2m_set_mem_access_multi(struct domain *d,
> return rc;
> }
>
> -int p2m_get_mem_access(struct domain *d, gfn_t gfn, xenmem_access_t *access)
> +int p2m_get_mem_access(struct domain *d, gfn_t gfn, xenmem_access_t *access,
> + unsigned int altp2m_idx)
> {
> - struct p2m_domain *p2m = p2m_get_hostp2m(d);
> + struct p2m_domain *p2m;
> +
> + if ( !altp2m_active(d) )
> + {
> + if ( altp2m_idx )
> + return -EINVAL;
> +
> + p2m = p2m_get_hostp2m(d);
> + }
> + else
> + {
> + if ( altp2m_idx >= MAX_ALTP2M ||
> + d->arch.altp2m_eptp[altp2m_idx] == mfn_x(INVALID_MFN) )
> + return -EINVAL;
> +
> + p2m = d->arch.altp2m_p2m[altp2m_idx];
> + }
>
> return _p2m_get_mem_access(p2m, gfn, access);
> }
> diff --git a/xen/common/mem_access.c b/xen/common/mem_access.c
> index 1bf6824442..010e6f8dbf 100644
> --- a/xen/common/mem_access.c
> +++ b/xen/common/mem_access.c
> @@ -99,7 +99,7 @@ int mem_access_memop(unsigned long cmd,
> if ( (mao.pfn > domain_get_maximum_gpfn(d)) && mao.pfn != ~0ull )
> break;
>
> - rc = p2m_get_mem_access(d, _gfn(mao.pfn), &access);
> + rc = p2m_get_mem_access(d, _gfn(mao.pfn), &access, 0);
> if ( rc != 0 )
> break;
>
> diff --git a/xen/include/public/hvm/hvm_op.h b/xen/include/public/hvm/hvm_op.h
> index bbba99e5f5..bbb0aa984a 100644
> --- a/xen/include/public/hvm/hvm_op.h
> +++ b/xen/include/public/hvm/hvm_op.h
> @@ -234,6 +234,7 @@ struct xen_hvm_altp2m_view {
> typedef struct xen_hvm_altp2m_view xen_hvm_altp2m_view_t;
> DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_view_t);
>
> +#if __XEN_INTERFACE_VERSION__ < 0x00040a00
> struct xen_hvm_altp2m_set_mem_access {
> /* view */
> uint16_t view;
> @@ -245,6 +246,19 @@ struct xen_hvm_altp2m_set_mem_access {
> };
> typedef struct xen_hvm_altp2m_set_mem_access xen_hvm_altp2m_set_mem_access_t;
> DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_set_mem_access_t);
> +#endif /* __XEN_INTERFACE_VERSION__ < 0x00040a00 */
> +
> +struct xen_hvm_altp2m_mem_access {
> + /* view */
> + uint16_t view;
> + /* Memory type */
> + uint16_t hvmmem_access; /* xenmem_access_t */
A structure name with "mem_access" having a variable name
"hvmmem_access" and a comment saying "xenmem_access". This is
confusing. I understand that you copy/pasted this from the existing op
but it doesn't look good. Perhaps fix both if we are touching it?
Also, in public/memory.h the width of access is uint8_t so I'm not
sure why the discrepancy.
> + uint32_t pad;
> + /* gfn */
> + uint64_t gfn;
> +};
> +typedef struct xen_hvm_altp2m_mem_access xen_hvm_altp2m_mem_access_t;
> +DEFINE_XEN_GUEST_HANDLE(xen_hvm_altp2m_mem_access_t);
>
> struct xen_hvm_altp2m_set_mem_access_multi {
> /* view */
> @@ -296,6 +310,8 @@ struct xen_hvm_altp2m_op {
> #define HVMOP_altp2m_change_gfn 8
> /* Set access for an array of pages */
> #define HVMOP_altp2m_set_mem_access_multi 9
> +/* Get the access of a page of memory from a certain view */
> +#define HVMOP_altp2m_get_mem_access 10
> domid_t domain;
> uint16_t pad1;
> uint32_t pad2;
> @@ -303,7 +319,10 @@ struct xen_hvm_altp2m_op {
> struct xen_hvm_altp2m_domain_state domain_state;
> struct xen_hvm_altp2m_vcpu_enable_notify enable_notify;
> struct xen_hvm_altp2m_view view;
> +#if __XEN_INTERFACE_VERSION__ < 0x00040a00
> struct xen_hvm_altp2m_set_mem_access set_mem_access;
> +#endif /* __XEN_INTERFACE_VERSION__ < 0x00040a00 */
> + struct xen_hvm_altp2m_mem_access mem_access;
> struct xen_hvm_altp2m_change_gfn change_gfn;
> struct xen_hvm_altp2m_set_mem_access_multi set_mem_access_multi;
> uint8_t pad[64];
> diff --git a/xen/include/public/xen-compat.h b/xen/include/public/xen-compat.h
> index b67365340b..fa6ffb72e8 100644
> --- a/xen/include/public/xen-compat.h
> +++ b/xen/include/public/xen-compat.h
> @@ -27,7 +27,7 @@
> #ifndef __XEN_PUBLIC_XEN_COMPAT_H__
> #define __XEN_PUBLIC_XEN_COMPAT_H__
>
> -#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040900
> +#define __XEN_LATEST_INTERFACE_VERSION__ 0x00040a00
>
> #if defined(__XEN__) || defined(__XEN_TOOLS__)
> /* Xen is built with matching headers and implements the latest interface. */
> diff --git a/xen/include/xen/mem_access.h b/xen/include/xen/mem_access.h
> index 7e95eab81c..7348f81233 100644
> --- a/xen/include/xen/mem_access.h
> +++ b/xen/include/xen/mem_access.h
> @@ -76,7 +76,8 @@ long p2m_set_mem_access_multi(struct domain *d,
> * Get access type for a gfn.
> * If gfn == INVALID_GFN, gets the default access type.
> */
> -int p2m_get_mem_access(struct domain *d, gfn_t gfn, xenmem_access_t *access);
> +int p2m_get_mem_access(struct domain *d, gfn_t gfn, xenmem_access_t *access,
> + unsigned int altp2m_idx);
>
> #ifdef CONFIG_MEM_ACCESS
> int mem_access_memop(unsigned long cmd,
> --
> 2.18.0
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