|
[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH v3 07/14] xen: Introduce HAS_M2P config and use to protect mfn_to_gmfn call
While Arm never had a M2P, the implementation of mfn_to_gmfn is pretty
bogus as we directly return the MFN passed in parameter.
Thankfully, the use of mfn_to_gmfn is pretty limited on Arm today. There
are only 3 callers:
- iommu_hwdom_init: mfn_to_gmfn is used for creating IOMMU
page-tables when the P2M is not shared with the IOMMU. No issues so
far as Arm does not yet support non-shared P2M case.
- memory_exchange: Arm cannot not use it because steal_page is not
implemented.
- getdomaininfo: Toolstack may map the shared page. It looks like
this is mostly used for mapping the P2M of PV guest. Therefore the
issue might be minor.
Implementing the M2P on Arm is not planned. The M2P would require significant
amount of VA address (very tough on 32-bit) that can hardly be justified with
the current use of mfn_to_gmfn.
- iommu_hwdom_init: mfn_to_gmfn is used because the creating of the
IOMMU page-tables is delayed until the first device is assigned.
In the embedded case, we will known in most of the times what
devices are assigned during the domain creation. So it is possible
to take to enable the IOMMU from start. See [1] for the patch.
- memory_exchange: This does not work and I haven't seen any
request for it so far.
- getdomaininfo: The structure on Arm does not seem to contain a lot
of useful information on Arm. It is unclear whether we want to
allow the toolstack mapping it on Arm.
This patch introduces a config option HAS_M2P to tell whether an
architecture implements the M2P.
- iommu_hwdom_init: For now, we require the M2P support when the IOMMU
is not sharing the P2M.
- memory_exchange: The hypercall is marked as not supported when the
M2P does not exist.
- getdomaininfo: A new helper is introduced to wrap the call to
mfn_to_gfn/mfn_to_gmfn. For Arm, a fixed value will be provided that will
fail on mapping if used.
[1] https://patchwork.kernel.org/patch/9719913/
Signed-off-by Julien Grall <julien.grall@xxxxxxx>
---
Cc: oleksandr_tyshchenko@xxxxxxxx
Cc: andrii_anisov@xxxxxxxx
Changes in v3:
- Move the BUG_ON() in domain_shared_info_gfn()
- Use a fixed value when the field shared_info_frame is not
supported.
- Add an ASSERT_UNREACHABLE in iommu_hwdom_init + move printk
within the #ifdef.
Changes in v2:
- Add a warning in public headers
- Constify local variable in domain_shared_info_gfn
- Invert the naming (_d / d) in domain_shared_info_gfn
- Use -EOPNOTSUPP rather than -ENOSYS
- Rework how the memory_exchange hypercall is removed from Arm
---
xen/arch/x86/Kconfig | 1 +
xen/common/Kconfig | 3 +++
xen/common/domctl.c | 9 +++++++--
xen/common/memory.c | 4 ++++
xen/drivers/passthrough/iommu.c | 8 +++++++-
xen/include/asm-arm/domain.h | 5 +++++
xen/include/public/domctl.h | 6 ++++++
xen/include/xen/domain.h | 12 ++++++++++++
8 files changed, 45 insertions(+), 3 deletions(-)
diff --git a/xen/arch/x86/Kconfig b/xen/arch/x86/Kconfig
index f502d765ba..c78eaf820a 100644
--- a/xen/arch/x86/Kconfig
+++ b/xen/arch/x86/Kconfig
@@ -17,6 +17,7 @@ config X86
select HAS_IOPORTS
select HAS_KEXEC
select MEM_ACCESS_ALWAYS_ON
+ select HAS_M2P
select HAS_MEM_PAGING
select HAS_MEM_SHARING
select HAS_NS16550
diff --git a/xen/common/Kconfig b/xen/common/Kconfig
index 10a759b31f..aae4c93002 100644
--- a/xen/common/Kconfig
+++ b/xen/common/Kconfig
@@ -66,6 +66,9 @@ config HAS_GDBSX
config HAS_IOPORTS
bool
+config HAS_M2P
+ bool
+
config NEEDS_LIBELF
bool
diff --git a/xen/common/domctl.c b/xen/common/domctl.c
index bade9a63b1..5746daeb80 100644
--- a/xen/common/domctl.c
+++ b/xen/common/domctl.c
@@ -154,6 +154,7 @@ void getdomaininfo(struct domain *d, struct
xen_domctl_getdomaininfo *info)
u64 cpu_time = 0;
int flags = XEN_DOMINF_blocked;
struct vcpu_runstate_info runstate;
+ gfn_t shared_info_frame;
info->domain = d->domain_id;
info->max_vcpu_id = XEN_INVALID_MAX_VCPU_ID;
@@ -205,8 +206,12 @@ void getdomaininfo(struct domain *d, struct
xen_domctl_getdomaininfo *info)
info->outstanding_pages = d->outstanding_pages;
info->shr_pages = atomic_read(&d->shr_pages);
info->paged_pages = atomic_read(&d->paged_pages);
- info->shared_info_frame = mfn_to_gmfn(d, virt_to_mfn(d->shared_info));
- BUG_ON(SHARED_M2P(info->shared_info_frame));
+
+ shared_info_frame = domain_shared_info_gfn(d);
+ if ( gfn_eq(shared_info_frame, INVALID_GFN) )
+ info->shared_info_frame = XEN_INVALID_SHARED_INFO_FRAME;
+ else
+ info->shared_info_frame = gfn_x(shared_info_frame);
info->cpupool = d->cpupool ? d->cpupool->cpupool_id : CPUPOOLID_NONE;
diff --git a/xen/common/memory.c b/xen/common/memory.c
index 520d6f4803..7a94250e50 100644
--- a/xen/common/memory.c
+++ b/xen/common/memory.c
@@ -504,6 +504,7 @@ static bool propagate_node(unsigned int xmf, unsigned int
*memflags)
static long memory_exchange(XEN_GUEST_HANDLE_PARAM(xen_memory_exchange_t) arg)
{
+#ifdef CONFIG_M2P
struct xen_memory_exchange exch;
PAGE_LIST_HEAD(in_chunk_list);
PAGE_LIST_HEAD(out_chunk_list);
@@ -794,6 +795,9 @@ static long
memory_exchange(XEN_GUEST_HANDLE_PARAM(xen_memory_exchange_t) arg)
if ( __copy_field_to_guest(arg, &exch, nr_exchanged) )
rc = -EFAULT;
return rc;
+#else /* !CONFIG_M2P */
+ return -EOPNOTSUPP;
+#endif
}
int xenmem_add_to_physmap(struct domain *d, struct xen_add_to_physmap *xatp,
diff --git a/xen/drivers/passthrough/iommu.c b/xen/drivers/passthrough/iommu.c
index 79ec6719f5..43174176c2 100644
--- a/xen/drivers/passthrough/iommu.c
+++ b/xen/drivers/passthrough/iommu.c
@@ -188,9 +188,10 @@ void __hwdom_init iommu_hwdom_init(struct domain *d)
hd->need_sync = iommu_hwdom_strict && !iommu_use_hap_pt(d);
if ( need_iommu_pt_sync(d) )
{
+ int rc = 0;
+#ifdef CONFIG_HAS_M2P
struct page_info *page;
unsigned int i = 0, flush_flags = 0;
- int rc = 0;
page_list_for_each ( page, &d->page_list )
{
@@ -221,6 +222,11 @@ void __hwdom_init iommu_hwdom_init(struct domain *d)
if ( rc )
printk(XENLOG_WARNING "d%d: IOMMU mapping failed: %d\n",
d->domain_id, rc);
+#else
+ ASSERT_UNREACHABLE();
+ rc = -EOPNOTSUPP;
+#endif
+
}
hd->platform_ops->hwdom_init(d);
diff --git a/xen/include/asm-arm/domain.h b/xen/include/asm-arm/domain.h
index 312fec8932..d61b0188da 100644
--- a/xen/include/asm-arm/domain.h
+++ b/xen/include/asm-arm/domain.h
@@ -267,6 +267,11 @@ static inline void free_vcpu_guest_context(struct
vcpu_guest_context *vgc)
static inline void arch_vcpu_block(struct vcpu *v) {}
+static inline gfn_t domain_shared_info_gfn(struct domain *d)
+{
+ return INVALID_GFN;
+}
+
#endif /* __ASM_DOMAIN_H__ */
/*
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 19486d5e32..9e9d28a8da 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -118,6 +118,12 @@ struct xen_domctl_getdomaininfo {
uint64_aligned_t outstanding_pages;
uint64_aligned_t shr_pages;
uint64_aligned_t paged_pages;
+#define XEN_INVALID_SHARED_INFO_FRAME (~(uint64_t)0)
+ /*
+ * GFN of shared_info struct. Some architectures (e.g Arm) may not
+ * provide a mappable address in the field. In that case, the field
+ * will be set to XEN_INVALID_SHARED_INFO_FRAME.
+ */
uint64_aligned_t shared_info_frame; /* GMFN of shared_info struct */
uint64_aligned_t cpu_time;
uint32_t nr_online_vcpus; /* Number of VCPUs currently online. */
diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
index d1bfc82f57..f5b9f3ef2a 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -118,4 +118,16 @@ struct vnuma_info {
void vnuma_destroy(struct vnuma_info *vnuma);
+#ifdef CONFIG_HAS_M2P
+#define domain_shared_info_gfn(d) ({ \
+ const struct domain *d_ = (d); \
+ gfn_t gfn_; \
+ \
+ gfn_ = mfn_to_gfn(d_, _mfn(__virt_to_mfn(d_->shared_info)));\
+ BUG_ON(SHARED_M2P(gfn_x(gfn_))); \
+ \
+ gfn_; \
+})
+#endif
+
#endif /* __XEN_DOMAIN_H__ */
--
2.11.0
_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxxx
https://lists.xenproject.org/mailman/listinfo/xen-devel
|
 |
Lists.xenproject.org is hosted with RackSpace, monitoring our |