| Message ID | 20200815111557.29564-1-jgross@suse.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | mini-os: correct memory access rights for pvh mode | expand |
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 >
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.
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 */
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(-)