arch/x86/x86_hvm.S | 2 +- include/x86/arch_mm.h | 18 ++++++++++++------ include/x86/os.h | 1 + 3 files changed, 14 insertions(+), 7 deletions(-)
When running as a PVH guest the memory access rights are not set
correctly: _PAGE_USER should not be set and CR0.WP should be set.
Especially CR0.WP is important in order to let the allocate on
demand feature work, as it requires a page fault when writing to a
read-only page.
Signed-off-by: Juergen Gross <jgross@suse.com>
---
arch/x86/x86_hvm.S | 2 +-
include/x86/arch_mm.h | 18 ++++++++++++------
include/x86/os.h | 1 +
3 files changed, 14 insertions(+), 7 deletions(-)
diff --git a/arch/x86/x86_hvm.S b/arch/x86/x86_hvm.S
index 6e8ad98..42a5f02 100644
--- a/arch/x86/x86_hvm.S
+++ b/arch/x86/x86_hvm.S
@@ -20,7 +20,7 @@ _start:
#endif /* __x86_64__ */
mov %cr0, %eax
- or $X86_CR0_PG, %eax
+ or $(X86_CR0_PG | X86_CR0_WP), %eax
mov %eax, %cr0
lgdt gdt_ptr
diff --git a/include/x86/arch_mm.h b/include/x86/arch_mm.h
index cbbeb21..ffbec5a 100644
--- a/include/x86/arch_mm.h
+++ b/include/x86/arch_mm.h
@@ -171,17 +171,23 @@ typedef unsigned long pgentry_t;
#define _PAGE_PSE CONST(0x080)
#define _PAGE_GLOBAL CONST(0x100)
+#ifdef CONFIG_PARAVIRT
+#define PAGE_USER _PAGE_USER
+#else
+#define PAGE_USER CONST(0)
+#endif
+
#if defined(__i386__)
#define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED)
#define L1_PROT_RO (_PAGE_PRESENT|_PAGE_ACCESSED)
-#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY |_PAGE_USER)
+#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY |PAGE_USER)
#define L3_PROT (_PAGE_PRESENT)
#elif defined(__x86_64__)
-#define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_USER)
-#define L1_PROT_RO (_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_USER)
-#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_USER)
-#define L3_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_USER)
-#define L4_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_USER)
+#define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|PAGE_USER)
+#define L1_PROT_RO (_PAGE_PRESENT|_PAGE_ACCESSED|PAGE_USER)
+#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|PAGE_USER)
+#define L3_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|PAGE_USER)
+#define L4_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|PAGE_USER)
#endif /* __i386__ || __x86_64__ */
/* flags for ioremap */
diff --git a/include/x86/os.h b/include/x86/os.h
index a73b63e..46a824d 100644
--- a/include/x86/os.h
+++ b/include/x86/os.h
@@ -27,6 +27,7 @@
#define MSR_EFER 0xc0000080
#define _EFER_LME 8 /* Long mode enable */
+#define X86_CR0_WP 0x00010000 /* Write protect */
#define X86_CR0_PG 0x80000000 /* Paging */
#define X86_CR4_PAE 0x00000020 /* enable physical address extensions */
#define X86_CR4_OSFXSR 0x00000200 /* enable fast FPU save and restore */
--
2.26.2
Juergen Gross, le sam. 15 août 2020 13:15:57 +0200, a ecrit: > When running as a PVH guest the memory access rights are not set > correctly: _PAGE_USER should not be set and CR0.WP should be set. > Especially CR0.WP is important in order to let the allocate on > demand feature work, as it requires a page fault when writing to a > read-only page. > > Signed-off-by: Juergen Gross <jgross@suse.com> Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> > --- > arch/x86/x86_hvm.S | 2 +- > include/x86/arch_mm.h | 18 ++++++++++++------ > include/x86/os.h | 1 + > 3 files changed, 14 insertions(+), 7 deletions(-) > > diff --git a/arch/x86/x86_hvm.S b/arch/x86/x86_hvm.S > index 6e8ad98..42a5f02 100644 > --- a/arch/x86/x86_hvm.S > +++ b/arch/x86/x86_hvm.S > @@ -20,7 +20,7 @@ _start: > #endif /* __x86_64__ */ > > mov %cr0, %eax > - or $X86_CR0_PG, %eax > + or $(X86_CR0_PG | X86_CR0_WP), %eax > mov %eax, %cr0 > > lgdt gdt_ptr > diff --git a/include/x86/arch_mm.h b/include/x86/arch_mm.h > index cbbeb21..ffbec5a 100644 > --- a/include/x86/arch_mm.h > +++ b/include/x86/arch_mm.h > @@ -171,17 +171,23 @@ typedef unsigned long pgentry_t; > #define _PAGE_PSE CONST(0x080) > #define _PAGE_GLOBAL CONST(0x100) > > +#ifdef CONFIG_PARAVIRT > +#define PAGE_USER _PAGE_USER > +#else > +#define PAGE_USER CONST(0) > +#endif > + > #if defined(__i386__) > #define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED) > #define L1_PROT_RO (_PAGE_PRESENT|_PAGE_ACCESSED) > -#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY |_PAGE_USER) > +#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY |PAGE_USER) > #define L3_PROT (_PAGE_PRESENT) > #elif defined(__x86_64__) > -#define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_USER) > -#define L1_PROT_RO (_PAGE_PRESENT|_PAGE_ACCESSED|_PAGE_USER) > -#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_USER) > -#define L3_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_USER) > -#define L4_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|_PAGE_USER) > +#define L1_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|PAGE_USER) > +#define L1_PROT_RO (_PAGE_PRESENT|_PAGE_ACCESSED|PAGE_USER) > +#define L2_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|PAGE_USER) > +#define L3_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|PAGE_USER) > +#define L4_PROT (_PAGE_PRESENT|_PAGE_RW|_PAGE_ACCESSED|_PAGE_DIRTY|PAGE_USER) > #endif /* __i386__ || __x86_64__ */ > > /* flags for ioremap */ > diff --git a/include/x86/os.h b/include/x86/os.h > index a73b63e..46a824d 100644 > --- a/include/x86/os.h > +++ b/include/x86/os.h > @@ -27,6 +27,7 @@ > #define MSR_EFER 0xc0000080 > #define _EFER_LME 8 /* Long mode enable */ > > +#define X86_CR0_WP 0x00010000 /* Write protect */ > #define X86_CR0_PG 0x80000000 /* Paging */ > #define X86_CR4_PAE 0x00000020 /* enable physical address extensions */ > #define X86_CR4_OSFXSR 0x00000200 /* enable fast FPU save and restore */ > -- > 2.26.2 > -- Samuel <y> la vraie vie, c'est quand le prompt passe de $ à #
On Sat, Aug 15, 2020 at 11:40:02PM +0200, Samuel Thibault wrote: > Juergen Gross, le sam. 15 août 2020 13:15:57 +0200, a ecrit: > > When running as a PVH guest the memory access rights are not set > > correctly: _PAGE_USER should not be set and CR0.WP should be set. > > Especially CR0.WP is important in order to let the allocate on > > demand feature work, as it requires a page fault when writing to a > > read-only page. > > > > Signed-off-by: Juergen Gross <jgross@suse.com> > > Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org> Applied.
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