Hoist the l1e_from_pfn(zero_pfn, __PAGE_HYPERVISOR_RO) calculation out of the
loop, and switch the code over to using mfn_t.
Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
---
CC: Jan Beulich <jbeul...@suse.com>
CC: Wei Liu <wei.l...@citrix.com>
---
xen/arch/x86/pv/descriptor-tables.c | 17 ++++++++++-------
1 file changed, 10 insertions(+), 7 deletions(-)
diff --git a/xen/arch/x86/pv/descriptor-tables.c
b/xen/arch/x86/pv/descriptor-tables.c
index e31c97e..d1c4296 100644
--- a/xen/arch/x86/pv/descriptor-tables.c
+++ b/xen/arch/x86/pv/descriptor-tables.c
@@ -37,18 +37,21 @@
void pv_destroy_gdt(struct vcpu *v)
{
- l1_pgentry_t *pl1e;
+ l1_pgentry_t *pl1e = pv_gdt_ptes(v);
+ mfn_t zero_mfn = _mfn(virt_to_mfn(zero_page));
+ l1_pgentry_t zero_l1e = l1e_from_mfn(zero_mfn, __PAGE_HYPERVISOR_RO);
unsigned int i;
- unsigned long pfn, zero_pfn = PFN_DOWN(__pa(zero_page));
v->arch.pv_vcpu.gdt_ents = 0;
- pl1e = pv_gdt_ptes(v);
for ( i = 0; i < FIRST_RESERVED_GDT_PAGE; i++ )
{
- pfn = l1e_get_pfn(pl1e[i]);
- if ( (l1e_get_flags(pl1e[i]) & _PAGE_PRESENT) && pfn != zero_pfn )
- put_page_and_type(mfn_to_page(_mfn(pfn)));
- l1e_write(&pl1e[i], l1e_from_pfn(zero_pfn, __PAGE_HYPERVISOR_RO));
+ mfn_t mfn = l1e_get_mfn(pl1e[i]);
+
+ if ( (l1e_get_flags(pl1e[i]) & _PAGE_PRESENT) &&
+ !mfn_eq(mfn, zero_mfn) )
+ put_page_and_type(mfn_to_page(mfn));
+
+ l1e_write(&pl1e[i], zero_l1e);
v->arch.pv_vcpu.gdt_frames[i] = 0;
}
}
--
2.1.4
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