From: Jan Beulich <jbeulich@suse.com>
To: "xen-devel@lists.xenproject.org" <xen-devel@lists.xenproject.org>
Cc: "Andrew Cooper" <andrew.cooper3@citrix.com>,
"Wei Liu" <wl@xen.org>, "Roger Pau Monné" <roger.pau@citrix.com>
Subject: [PATCH v3 3/3] x86/PV: polish pv_set_gdt()
Date: Wed, 20 May 2020 09:54:39 +0200 [thread overview]
Message-ID: <ceae9c78-d0be-c1eb-88fc-c036b050f668@suse.com> (raw)
In-Reply-To: <cbed3c45-3685-4bce-9719-93b1e8a2599a@suse.com>
There's no need to invoke get_page_from_gfn(), and there's also no need
to update the passed in frames[]. Invoke get_page_and_type() directly.
Also make the function's frames[] parameter const, change its return
type to int, and drop the bogus casts from two of its invocations.
Finally a little bit of cosmetics.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Acked-by: Andrew Cooper <andrew.cooper3@citrix.com>
--- a/xen/arch/x86/domain.c
+++ b/xen/arch/x86/domain.c
@@ -1099,7 +1099,7 @@ int arch_set_info_guest(
return rc;
if ( !compat )
- rc = (int)pv_set_gdt(v, c.nat->gdt_frames, c.nat->gdt_ents);
+ rc = pv_set_gdt(v, c.nat->gdt_frames, c.nat->gdt_ents);
else
{
unsigned long gdt_frames[ARRAY_SIZE(v->arch.pv.gdt_frames)];
@@ -1107,7 +1107,7 @@ int arch_set_info_guest(
for ( i = 0; i < nr_gdt_frames; ++i )
gdt_frames[i] = c.cmp->gdt_frames[i];
- rc = (int)pv_set_gdt(v, gdt_frames, c.cmp->gdt_ents);
+ rc = pv_set_gdt(v, gdt_frames, c.cmp->gdt_ents);
}
if ( rc != 0 )
return rc;
--- a/xen/arch/x86/pv/descriptor-tables.c
+++ b/xen/arch/x86/pv/descriptor-tables.c
@@ -81,7 +81,8 @@ void pv_destroy_gdt(struct vcpu *v)
}
}
-long pv_set_gdt(struct vcpu *v, unsigned long *frames, unsigned int entries)
+int pv_set_gdt(struct vcpu *v, const unsigned long frames[],
+ unsigned int entries)
{
struct domain *d = v->domain;
l1_pgentry_t *pl1e;
@@ -95,17 +96,11 @@ long pv_set_gdt(struct vcpu *v, unsigned
/* Check the pages in the new GDT. */
for ( i = 0; i < nr_frames; i++ )
{
- struct page_info *page;
+ mfn_t mfn = _mfn(frames[i]);
- page = get_page_from_gfn(d, frames[i], NULL, P2M_ALLOC);
- if ( !page )
+ if ( !mfn_valid(mfn) ||
+ !get_page_and_type(mfn_to_page(mfn), d, PGT_seg_desc_page) )
goto fail;
- if ( !get_page_type(page, PGT_seg_desc_page) )
- {
- put_page(page);
- goto fail;
- }
- frames[i] = mfn_x(page_to_mfn(page));
}
/* Tear down the old GDT. */
@@ -124,9 +119,8 @@ long pv_set_gdt(struct vcpu *v, unsigned
fail:
while ( i-- > 0 )
- {
put_page_and_type(mfn_to_page(_mfn(frames[i])));
- }
+
return -EINVAL;
}
--- a/xen/include/asm-x86/pv/mm.h
+++ b/xen/include/asm-x86/pv/mm.h
@@ -25,7 +25,8 @@
int pv_ro_page_fault(unsigned long addr, struct cpu_user_regs *regs);
-long pv_set_gdt(struct vcpu *v, unsigned long *frames, unsigned int entries);
+int pv_set_gdt(struct vcpu *v, const unsigned long frames[],
+ unsigned int entries);
void pv_destroy_gdt(struct vcpu *v);
bool pv_map_ldt_shadow_page(unsigned int off);
@@ -43,8 +44,8 @@ static inline int pv_ro_page_fault(unsig
return 0;
}
-static inline long pv_set_gdt(struct vcpu *v, unsigned long *frames,
- unsigned int entries)
+static inline int pv_set_gdt(struct vcpu *v, const unsigned long frames[],
+ unsigned int entries)
{ ASSERT_UNREACHABLE(); return -EINVAL; }
static inline void pv_destroy_gdt(struct vcpu *v) { ASSERT_UNREACHABLE(); }
prev parent reply other threads:[~2020-05-20 7:54 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-20 7:50 [PATCH v3 0/3] x86: XSA-298 follow-up Jan Beulich
2020-05-20 7:53 ` [PATCH v3 1/3] x86: relax GDT check in arch_set_info_guest() Jan Beulich
2020-05-20 10:20 ` Roger Pau Monné
2020-05-22 13:27 ` Andrew Cooper
2020-05-22 14:14 ` Jan Beulich
2020-05-20 7:54 ` [PATCH v3 2/3] x86: relax LDT " Jan Beulich
2020-05-20 7:54 ` Jan Beulich [this message]
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