| Message ID | dd39dfd18bcae4e5116597d4e9c186249aa15850.1671098103.git.baskov@ispras.ru (mailing list archive) |
|---|---|
| State | Handled Elsewhere |
| Headers | show |
| Series | x86_64: Improvements at compressed kernel stage | expand |
On Thu, 15 Dec 2022 at 13:40, Evgeniy Baskov <baskov@ispras.ru> wrote: > > After every implicit mapping is removed, this code is no longer needed. > > Remove memory mapping from page fault handler to ensure that there are > no hidden invalid memory accesses. > > Tested-by: Mario Limonciello <mario.limonciello@amd.com> > Tested-by: Peter Jones <pjones@redhat.com> > Signed-off-by: Evgeniy Baskov <baskov@ispras.ru> Reviewed-by: Ard Biesheuvel <ardb@kernel.org> > --- > arch/x86/boot/compressed/ident_map_64.c | 26 ++++++++++--------------- > 1 file changed, 10 insertions(+), 16 deletions(-) > > diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c > index fec795a4ce23..ba5108c58a4e 100644 > --- a/arch/x86/boot/compressed/ident_map_64.c > +++ b/arch/x86/boot/compressed/ident_map_64.c > @@ -386,27 +386,21 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code) > { > unsigned long address = native_read_cr2(); > unsigned long end; > - bool ghcb_fault; > + char *msg; > > - ghcb_fault = sev_es_check_ghcb_fault(address); > + if (sev_es_check_ghcb_fault(address)) > + msg = "Page-fault on GHCB page:"; > + else > + msg = "Unexpected page-fault:"; > > address &= PMD_MASK; > end = address + PMD_SIZE; > > /* > - * Check for unexpected error codes. Unexpected are: > - * - Faults on present pages > - * - User faults > - * - Reserved bits set > - */ > - if (error_code & (X86_PF_PROT | X86_PF_USER | X86_PF_RSVD)) > - do_pf_error("Unexpected page-fault:", error_code, address, regs->ip); > - else if (ghcb_fault) > - do_pf_error("Page-fault on GHCB page:", error_code, address, regs->ip); > - > - /* > - * Error code is sane - now identity map the 2M region around > - * the faulting address. > + * Since all memory allocations are made explicit > + * now, every page fault at this stage is an > + * error and the error handler is there only > + * for debug purposes. > */ > - kernel_add_identity_map(address, end, MAP_WRITE); > + do_pf_error(msg, error_code, address, regs->ip); > } > -- > 2.37.4 >
diff --git a/arch/x86/boot/compressed/ident_map_64.c b/arch/x86/boot/compressed/ident_map_64.c index fec795a4ce23..ba5108c58a4e 100644 --- a/arch/x86/boot/compressed/ident_map_64.c +++ b/arch/x86/boot/compressed/ident_map_64.c @@ -386,27 +386,21 @@ void do_boot_page_fault(struct pt_regs *regs, unsigned long error_code) { unsigned long address = native_read_cr2(); unsigned long end; - bool ghcb_fault; + char *msg; - ghcb_fault = sev_es_check_ghcb_fault(address); + if (sev_es_check_ghcb_fault(address)) + msg = "Page-fault on GHCB page:"; + else + msg = "Unexpected page-fault:"; address &= PMD_MASK; end = address + PMD_SIZE; /* - * Check for unexpected error codes. Unexpected are: - * - Faults on present pages - * - User faults - * - Reserved bits set - */ - if (error_code & (X86_PF_PROT | X86_PF_USER | X86_PF_RSVD)) - do_pf_error("Unexpected page-fault:", error_code, address, regs->ip); - else if (ghcb_fault) - do_pf_error("Page-fault on GHCB page:", error_code, address, regs->ip); - - /* - * Error code is sane - now identity map the 2M region around - * the faulting address. + * Since all memory allocations are made explicit + * now, every page fault at this stage is an + * error and the error handler is there only + * for debug purposes. */ - kernel_add_identity_map(address, end, MAP_WRITE); + do_pf_error(msg, error_code, address, regs->ip); }