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[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [xen staging] x86/mem-paging: use guest handle for XENMEM_paging_op_prep
commit 9f40699c956c10419a91db0ff8d0c985dd3b2800
Author: Jan Beulich <jbeulich@xxxxxxxx>
AuthorDate: Mon May 18 17:15:46 2020 +0200
Commit: Jan Beulich <jbeulich@xxxxxxxx>
CommitDate: Mon May 18 17:15:46 2020 +0200
x86/mem-paging: use guest handle for XENMEM_paging_op_prep
While it should have been this way from the beginning, not doing so will
become an actual problem with PVH Dom0. The interface change is binary
compatible, but requires tools side producers to be re-built.
Drop the bogus/unnecessary page alignment restriction on the input
buffer at the same time.
Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
Reviewed-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
Acked-by: Wei Liu <wl@xxxxxxx>
---
tools/libxc/xc_mem_paging.c | 41 ++++++++++++++++++++++-------------------
xen/arch/x86/mm/p2m.c | 15 ++++++---------
xen/include/asm-x86/p2m.h | 3 ++-
xen/include/public/memory.h | 8 ++++----
4 files changed, 34 insertions(+), 33 deletions(-)
diff --git a/tools/libxc/xc_mem_paging.c b/tools/libxc/xc_mem_paging.c
index a067706e5c..738f63ac20 100644
--- a/tools/libxc/xc_mem_paging.c
+++ b/tools/libxc/xc_mem_paging.c
@@ -26,15 +26,33 @@ static int xc_mem_paging_memop(xc_interface *xch, uint32_t
domain_id,
unsigned int op, uint64_t gfn, void *buffer)
{
xen_mem_paging_op_t mpo;
+ DECLARE_HYPERCALL_BOUNCE(buffer, XC_PAGE_SIZE,
+ XC_HYPERCALL_BUFFER_BOUNCE_IN);
+ int rc;
memset(&mpo, 0, sizeof(mpo));
mpo.op = op;
mpo.domain = domain_id;
mpo.gfn = gfn;
- mpo.buffer = (unsigned long) buffer;
- return do_memory_op(xch, XENMEM_paging_op, &mpo, sizeof(mpo));
+ if ( buffer )
+ {
+ if ( xc_hypercall_bounce_pre(xch, buffer) )
+ {
+ PERROR("Could not bounce memory for XENMEM_paging_op %u", op);
+ return -1;
+ }
+
+ set_xen_guest_handle(mpo.buffer, buffer);
+ }
+
+ rc = do_memory_op(xch, XENMEM_paging_op, &mpo, sizeof(mpo));
+
+ if ( buffer )
+ xc_hypercall_bounce_post(xch, buffer);
+
+ return rc;
}
int xc_mem_paging_enable(xc_interface *xch, uint32_t domain_id,
@@ -92,28 +110,13 @@ int xc_mem_paging_prep(xc_interface *xch, uint32_t
domain_id, uint64_t gfn)
int xc_mem_paging_load(xc_interface *xch, uint32_t domain_id,
uint64_t gfn, void *buffer)
{
- int rc, old_errno;
-
errno = EINVAL;
if ( !buffer )
return -1;
- if ( ((unsigned long) buffer) & (XC_PAGE_SIZE - 1) )
- return -1;
-
- if ( mlock(buffer, XC_PAGE_SIZE) )
- return -1;
-
- rc = xc_mem_paging_memop(xch, domain_id,
- XENMEM_paging_op_prep,
- gfn, buffer);
-
- old_errno = errno;
- munlock(buffer, XC_PAGE_SIZE);
- errno = old_errno;
-
- return rc;
+ return xc_mem_paging_memop(xch, domain_id, XENMEM_paging_op_prep,
+ gfn, buffer);
}
diff --git a/xen/arch/x86/mm/p2m.c b/xen/arch/x86/mm/p2m.c
index 9b7b0bf103..59b0b05ed5 100644
--- a/xen/arch/x86/mm/p2m.c
+++ b/xen/arch/x86/mm/p2m.c
@@ -1779,7 +1779,8 @@ void p2m_mem_paging_populate(struct domain *d, unsigned
long gfn_l)
* mfn if populate was called for gfn which was nominated but not evicted. In
* this case only the p2mt needs to be forwarded.
*/
-int p2m_mem_paging_prep(struct domain *d, unsigned long gfn_l, uint64_t buffer)
+int p2m_mem_paging_prep(struct domain *d, unsigned long gfn_l,
+ XEN_GUEST_HANDLE_64(const_uint8) buffer)
{
struct page_info *page = NULL;
p2m_type_t p2mt;
@@ -1788,13 +1789,9 @@ int p2m_mem_paging_prep(struct domain *d, unsigned long
gfn_l, uint64_t buffer)
mfn_t mfn;
struct p2m_domain *p2m = p2m_get_hostp2m(d);
int ret, page_extant = 1;
- const void *user_ptr = (const void *) buffer;
- if ( user_ptr )
- /* Sanity check the buffer and bail out early if trouble */
- if ( (buffer & (PAGE_SIZE - 1)) ||
- (!access_ok(user_ptr, PAGE_SIZE)) )
- return -EINVAL;
+ if ( !guest_handle_okay(buffer, PAGE_SIZE) )
+ return -EINVAL;
gfn_lock(p2m, gfn, 0);
@@ -1812,7 +1809,7 @@ int p2m_mem_paging_prep(struct domain *d, unsigned long
gfn_l, uint64_t buffer)
/* If the user did not provide a buffer, we disallow */
ret = -EINVAL;
- if ( unlikely(user_ptr == NULL) )
+ if ( unlikely(guest_handle_is_null(buffer)) )
goto out;
/* Get a free page */
ret = -ENOMEM;
@@ -1834,7 +1831,7 @@ int p2m_mem_paging_prep(struct domain *d, unsigned long
gfn_l, uint64_t buffer)
page_extant = 0;
guest_map = map_domain_page(mfn);
- ret = copy_from_user(guest_map, user_ptr, PAGE_SIZE);
+ ret = copy_from_guest(guest_map, buffer, PAGE_SIZE);
unmap_domain_page(guest_map);
if ( ret )
{
diff --git a/xen/include/asm-x86/p2m.h b/xen/include/asm-x86/p2m.h
index ace3573ae8..baebc8b6ef 100644
--- a/xen/include/asm-x86/p2m.h
+++ b/xen/include/asm-x86/p2m.h
@@ -741,7 +741,8 @@ void p2m_mem_paging_drop_page(struct domain *d, unsigned
long gfn,
/* Start populating a paged out frame */
void p2m_mem_paging_populate(struct domain *d, unsigned long gfn);
/* Prepare the p2m for paging a frame in */
-int p2m_mem_paging_prep(struct domain *d, unsigned long gfn, uint64_t buffer);
+int p2m_mem_paging_prep(struct domain *d, unsigned long gfn,
+ XEN_GUEST_HANDLE_64(const_uint8) buffer);
/* Resume normal operation (in case a domain was paused) */
struct vm_event_st;
void p2m_mem_paging_resume(struct domain *d, struct vm_event_st *rsp);
diff --git a/xen/include/public/memory.h b/xen/include/public/memory.h
index e56800357d..dbd35305df 100644
--- a/xen/include/public/memory.h
+++ b/xen/include/public/memory.h
@@ -396,10 +396,10 @@ struct xen_mem_paging_op {
uint8_t op; /* XENMEM_paging_op_* */
domid_t domain;
- /* PAGING_PREP IN: buffer to immediately fill page in */
- uint64_aligned_t buffer;
- /* Other OPs */
- uint64_aligned_t gfn; /* IN: gfn of page being operated on */
+ /* IN: (XENMEM_paging_op_prep) buffer to immediately fill page from */
+ XEN_GUEST_HANDLE_64(const_uint8) buffer;
+ /* IN: gfn of page being operated on */
+ uint64_aligned_t gfn;
};
typedef struct xen_mem_paging_op xen_mem_paging_op_t;
DEFINE_XEN_GUEST_HANDLE(xen_mem_paging_op_t);
--
generated by git-patchbot for /home/xen/git/xen.git#staging
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