Hi,
On 17/12/2019 21:15, Andrew Cooper wrote:
xc_dom_p2m() and dom->p2m_host[] implement a linear transform for translated
domains, but waste a substantial chunk of RAM doing so.
ARM literally never reads dom->p2m_host[] (because of the xc_dom_translated()
short circuit in xc_dom_p2m()). Drop it all.
x86 HVM does use dom->p2m_host[] for xc_domain_populate_physmap_exact() calls
when populating 4k pages. Reuse the same tactic from 2M/1G ranges and use an
on-stack array instead. Drop the memory allocation.
x86 PV guests do use dom->p2m_host[] as a non-identity transform. Rename the
field to pv_p2m to make it clear it is PV-only.
Nice cleanup! This will probably make slightly faster guest boot :).
@@ -359,7 +356,6 @@ static int populate_guest_memory(struct xc_dom_image *dom,
static int meminit(struct xc_dom_image *dom)
{
int i, rc;
- xen_pfn_t pfn;
uint64_t modbase;
uint64_t ramsize = (uint64_t)dom->total_pages << XC_PAGE_SHIFT;
@@ -423,11 +419,6 @@ static int meminit(struct xc_dom_image *dom)
assert(ramsize == 0); /* Too much RAM is rejected above */
dom->p2m_size = p2m_size;
Do we need to keep p2m_size?
Cheers,
--
Julien Grall
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