| Message ID | 20241022223954.432554-3-andrew.cooper3@citrix.com (mailing list archive) |
|---|---|
| State | New |
| Headers | show |
| Series | x86/boot: Improvements to move_memory() | expand |
On 10/22/24 18:39, Andrew Cooper wrote: > Given that soffs is the offset into the 2M superpage, > > start = (src - soffs) >> PAGE_SIFT > > is a complicated expression for the frame address of the containing superpage. > Except, start is converted straight back to a byte address to use, so the > shifting is unnecessary too. > > The only done with the mapped pointer is to have soffs added back on for the nit: think you dropped a word here, "The only done". > memmove() call. bootstrap_map_addr() passes through the offset, so we can > pass src directly in and simplify the memmove() call too. For the end mapping > address, this simplifies to just src + sz too. > > The same reasoning holds for dst and doffs. > > No functional change. > > Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> > --- > CC: Jan Beulich <JBeulich@suse.com> > CC: Roger Pau Monné <roger.pau@citrix.com> > CC: Daniel P. Smith <dpsmith@apertussolutions.com> After nit, Reviewed-by: Daniel P. Smith <dpsmith@apertussolutions.com>
diff --git a/xen/arch/x86/setup.c b/xen/arch/x86/setup.c index 46a0b3093c2c..152cd696d6c2 100644 --- a/xen/arch/x86/setup.c +++ b/xen/arch/x86/setup.c @@ -492,31 +492,26 @@ static void __init noinline move_memory( while ( size ) { - unsigned int start /* frame */; unsigned int end /* mapsz */; unsigned int soffs = src & mask; unsigned int doffs = dst & mask; unsigned int sz; void *d, *s; - start = (src - soffs) >> PAGE_SHIFT; end = soffs + size; if ( end > blksz ) end = blksz; sz = end - soffs; - s = bootstrap_map_addr(pfn_to_paddr(start), - pfn_to_paddr(start) + end); + s = bootstrap_map_addr(src, src + sz); - start = (dst - doffs) >> PAGE_SHIFT; end = doffs + size; if ( end > blksz ) end = blksz; if ( sz > end - doffs ) sz = end - doffs; - d = bootstrap_map_addr(pfn_to_paddr(start), - pfn_to_paddr(start) + end); + d = bootstrap_map_addr(dst, dst + sz); - memmove(d + doffs, s + soffs, sz); + memmove(d, s, sz); dst += sz; src += sz;
Given that soffs is the offset into the 2M superpage, start = (src - soffs) >> PAGE_SIFT is a complicated expression for the frame address of the containing superpage. Except, start is converted straight back to a byte address to use, so the shifting is unnecessary too. The only done with the mapped pointer is to have soffs added back on for the memmove() call. bootstrap_map_addr() passes through the offset, so we can pass src directly in and simplify the memmove() call too. For the end mapping address, this simplifies to just src + sz too. The same reasoning holds for dst and doffs. No functional change. Signed-off-by: Andrew Cooper <andrew.cooper3@citrix.com> --- CC: Jan Beulich <JBeulich@suse.com> CC: Roger Pau Monné <roger.pau@citrix.com> CC: Daniel P. Smith <dpsmith@apertussolutions.com> --- xen/arch/x86/setup.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-)