[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] [Xen-devel] [PATCH] x86: make certain memory sub-ops return valid values
When a domain's shared info field "max_pfn" is zero, domain_get_maximum_gpfn() so far returned ULONG_MAX, which do_memory_op() in turn converted to -1 (i.e. -EPERM). Make the former always return a sensible number (i.e. zero if the field was zero) and have the latter no longer truncate return values. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> --- a/xen/arch/x86/mm.c +++ b/xen/arch/x86/mm.c @@ -433,7 +433,7 @@ unsigned long domain_get_maximum_gpfn(st if ( is_hvm_domain(d) ) return p2m_get_hostp2m(d)->max_mapped_pfn; /* NB. PV guests specify nr_pfns rather than max_pfn so we adjust here. */ - return arch_get_max_pfn(d) - 1; + return (arch_get_max_pfn(d) ?: 1) - 1; } void share_xen_page_with_guest( --- a/xen/common/compat/memory.c +++ b/xen/common/compat/memory.c @@ -15,7 +15,8 @@ CHECK_TYPE(domid); int compat_memory_op(unsigned int cmd, XEN_GUEST_HANDLE_PARAM(void) compat) { - int rc, split, op = cmd & MEMOP_CMD_MASK; + int split, op = cmd & MEMOP_CMD_MASK; + long rc; unsigned int start_extent = cmd >> MEMOP_EXTENT_SHIFT; do @@ -204,7 +205,7 @@ int compat_memory_op(unsigned int cmd, X rc = do_memory_op(cmd, nat.hnd); if ( rc < 0 ) - return rc; + break; cmd = 0; if ( hypercall_xlat_continuation(&cmd, 0x02, nat.hnd, compat) ) @@ -326,5 +327,11 @@ int compat_memory_op(unsigned int cmd, X __HYPERVISOR_memory_op, "ih", cmd, compat); } while ( split > 0 ); + if ( unlikely(rc > INT_MAX) ) + return INT_MAX; + + if ( unlikely(rc < INT_MIN) ) + return INT_MIN; + return rc; } --- a/xen/common/memory.c +++ b/xen/common/memory.c @@ -545,14 +545,13 @@ static long memory_exchange(XEN_GUEST_HA long do_memory_op(unsigned long cmd, XEN_GUEST_HANDLE_PARAM(void) arg) { struct domain *d; - int rc, op; + long rc; unsigned int address_bits; unsigned long start_extent; struct xen_memory_reservation reservation; struct memop_args args; domid_t domid; - - op = cmd & MEMOP_CMD_MASK; + int op = cmd & MEMOP_CMD_MASK; switch ( op ) { Attachment:
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