Hi Andrew,
On 22/09/2020 19:56, Andrew Cooper wrote:
On 22/09/2020 19:20, Julien Grall wrote:
+
#endif /* __ASM_DOMAIN_H__ */
/*
diff --git a/xen/include/public/domctl.h b/xen/include/public/domctl.h
index 5c5e55ebcb76..7564df5e8374 100644
--- a/xen/include/public/domctl.h
+++ b/xen/include/public/domctl.h
@@ -136,6 +136,12 @@ 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)
We've already got INVALID_GFN as a constant used in the interface. Lets
not proliferate more.
This was my original approach (see [1]) but this was reworked because:
1) INVALID_GFN is not technically defined in the ABI. So the
toolstack has to hardcode the value in the check.
2) The value is different between 32-bit and 64-bit Arm as
INVALID_GFN is defined as an unsigned long.
So providing a new define is the right way to go.
There is nothing special about this field. It should not have a
dedicated constant, when a general one is the appropriate one to use.
libxl already has LIBXL_INVALID_GFN, which is already used.
Right, but that's imply it cannot be used by libxc as this would be a
layer violation.
If this isn't good enough, them the right thing to do is put a proper
INVALID_GFN in the tools interface.
That would be nice but I can see some issue on x86 given that we don't
consistenly define a GFN in the interface as a 64-bit value.
So would you still be happy to consider introducing XEN_INVALID_GFN in
the interface with some caveats?
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 cde0d9c7fe63..7281eb7b36c7 100644
--- a/xen/include/xen/domain.h
+++ b/xen/include/xen/domain.h
@@ -131,4 +131,16 @@ void vnuma_destroy(struct vnuma_info *vnuma);
static inline void vnuma_destroy(struct vnuma_info *vnuma) {
ASSERT(!vnuma); }
#endif
+#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_; \
+})
... this wants to be
#ifndef arch_shared_info_gfn
static inline gfn_t arch_shared_info_gfn(const struct domain *d) {
return INVALID_GFN; }
#endif
with
gfn_t arch_shared_info_gfn(const struct domain *d);
#define arch_shared_info_gfn arch_shared_info_gfn
in asm-x86/domain.h
and the actual implementation in arch/x86/domain.c
What's wrong with implement it in xen/domain.h? After all there is
nothing x86 specific in the implementation...
d->shared_info is allocated in arch specific code, not common code.
This macro assumes that __virt_to_mfn() is safe to call on the pointer.
That's a fair point. I will move the code in an x86 specific files.
Cheers,
--
Julien Grall
