| Message ID | 0972ea3c-c2a8-b0f4-ae25-132bdb798f6a@suse.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | x86: M2P maintenance adjustments (step 1) | expand |
On 06/08/2020 10:28, Jan Beulich wrote: > Add #ifdef-s (the 2nd one will be needed in particular, to guard the > uses of m2p_compat_vstart and HYPERVISOR_COMPAT_VIRT_START()) and fold > duplicate uses of elf_32bit(). > > Also adjust what gets logged: Avoid "compat32" when support isn't built > in, and don't assume ELF class <> ELFCLASS64 means ELFCLASS32. > > Signed-off-by: Jan Beulich <jbeulich@suse.com> Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> although with some further suggestions. > > --- a/xen/arch/x86/pv/dom0_build.c > +++ b/xen/arch/x86/pv/dom0_build.c > @@ -300,7 +300,6 @@ int __init dom0_construct_pv(struct doma > struct page_info *page = NULL; > start_info_t *si; > struct vcpu *v = d->vcpu[0]; > - unsigned long long value; > void *image_base = bootstrap_map(image); > unsigned long image_len = image->mod_end; > void *image_start = image_base + image_headroom; > @@ -357,27 +356,36 @@ int __init dom0_construct_pv(struct doma > goto out; > > /* compatibility check */ > + printk(" Xen kernel: 64-bit, lsb%s\n", > + IS_ENABLED(CONFIG_PV32) ? ", compat32" : ""); Here, and below, we print out lsb/msb for the ELF file. However, we don't use or check that it is actually lsb, and blindly assume that it is. Why bother printing it then? > compatible = 0; > machine = elf_uval(&elf, elf.ehdr, e_machine); > - printk(" Xen kernel: 64-bit, lsb, compat32\n"); > - if ( elf_32bit(&elf) && parms.pae == XEN_PAE_BIMODAL ) > - parms.pae = XEN_PAE_EXTCR3; > - if ( elf_32bit(&elf) && parms.pae && machine == EM_386 ) > + > +#ifdef CONFIG_PV32 > + if ( elf_32bit(&elf) ) > { > - if ( unlikely(rc = switch_compat(d)) ) > + if ( parms.pae == XEN_PAE_BIMODAL ) > + parms.pae = XEN_PAE_EXTCR3; > + if ( parms.pae && machine == EM_386 ) > { > - printk("Dom0 failed to switch to compat: %d\n", rc); > - return rc; > - } > + if ( unlikely(rc = switch_compat(d)) ) > + { > + printk("Dom0 failed to switch to compat: %d\n", rc); > + return rc; > + } > > - compatible = 1; > + compatible = 1; > + } > } > - if (elf_64bit(&elf) && machine == EM_X86_64) > +#endif > + > + if ( elf_64bit(&elf) && machine == EM_X86_64 ) > compatible = 1; > - printk(" Dom0 kernel: %s%s, %s, paddr %#" PRIx64 " -> %#" PRIx64 "\n", > - elf_64bit(&elf) ? "64-bit" : "32-bit", > - parms.pae ? ", PAE" : "", > - elf_msb(&elf) ? "msb" : "lsb", > + > + printk(" Dom0 kernel: %s-bit%s, %s, paddr %#" PRIx64 " -> %#" PRIx64 "\n", > + elf_64bit(&elf) ? "64" : elf_32bit(&elf) ? "32" : "??", > + parms.pae ? ", PAE" : "", > + elf_msb(&elf) ? "msb" : "lsb", > elf.pstart, elf.pend); > if ( elf.bsd_symtab_pstart ) > printk(" Dom0 symbol map %#" PRIx64 " -> %#" PRIx64 "\n", > @@ -405,23 +413,28 @@ int __init dom0_construct_pv(struct doma > if ( parms.pae == XEN_PAE_EXTCR3 ) > set_bit(VMASST_TYPE_pae_extended_cr3, &d->vm_assist); > > - if ( !pv_shim && (parms.virt_hv_start_low != UNSET_ADDR) && > - elf_32bit(&elf) ) > +#ifdef CONFIG_PV32 > + if ( elf_32bit(&elf) ) > { > - unsigned long mask = (1UL << L2_PAGETABLE_SHIFT) - 1; > - value = (parms.virt_hv_start_low + mask) & ~mask; > - BUG_ON(!is_pv_32bit_domain(d)); > - if ( value > __HYPERVISOR_COMPAT_VIRT_START ) > - panic("Domain 0 expects too high a hypervisor start address\n"); > - HYPERVISOR_COMPAT_VIRT_START(d) = > - max_t(unsigned int, m2p_compat_vstart, value); > - } > + if ( !pv_shim && (parms.virt_hv_start_low != UNSET_ADDR) ) > + { > + unsigned long mask = (1UL << L2_PAGETABLE_SHIFT) - 1; > + unsigned long value = (parms.virt_hv_start_low + mask) & ~mask; ROUNDUP() instead of opencoding it? > > - if ( (parms.p2m_base != UNSET_ADDR) && elf_32bit(&elf) ) > - { > - printk(XENLOG_WARNING "P2M table base ignored\n"); > - parms.p2m_base = UNSET_ADDR; > + BUG_ON(!is_pv_32bit_domain(d)); This BUG_ON() is useless. I suspect it is a vestigial safety measure from when the switch to compat was opencoded rather than using switch_compat() directly. > + if ( value > __HYPERVISOR_COMPAT_VIRT_START ) > + panic("Domain 0 expects too high a hypervisor start address\n"); It would be better to printk() and return -EINVAL, to be consistent with how other fatal errors are reported to the user. ~Andrew > + HYPERVISOR_COMPAT_VIRT_START(d) = > + max_t(unsigned int, m2p_compat_vstart, value); > + } > + > + if ( parms.p2m_base != UNSET_ADDR ) > + { > + printk(XENLOG_WARNING "P2M table base ignored\n"); > + parms.p2m_base = UNSET_ADDR; > + } > } > +#endif > > /* > * Why do we need this? The number of page-table frames depends on the >
On 06.08.2020 16:04, Andrew Cooper wrote: > On 06/08/2020 10:28, Jan Beulich wrote: >> Add #ifdef-s (the 2nd one will be needed in particular, to guard the >> uses of m2p_compat_vstart and HYPERVISOR_COMPAT_VIRT_START()) and fold >> duplicate uses of elf_32bit(). >> >> Also adjust what gets logged: Avoid "compat32" when support isn't built >> in, and don't assume ELF class <> ELFCLASS64 means ELFCLASS32. >> >> Signed-off-by: Jan Beulich <jbeulich@suse.com> > > Acked-by: Andrew Cooper <andrew.cooper3@citrix.com> although with some > further suggestions. Thanks. >> @@ -357,27 +356,36 @@ int __init dom0_construct_pv(struct doma >> goto out; >> >> /* compatibility check */ >> + printk(" Xen kernel: 64-bit, lsb%s\n", >> + IS_ENABLED(CONFIG_PV32) ? ", compat32" : ""); > > Here, and below, we print out lsb/msb for the ELF file. However, we > don't use or check that it is actually lsb, and blindly assume that it is. > > Why bother printing it then? To be honest, I'd rather add a check than drop the printing. However unlikely it may be to encounter an MSB ELF binary ... This particular one I'd like to do in a separate, follow-on patch though. I've addressed the other comments in what I intend to commit. Jan
--- a/xen/arch/x86/pv/dom0_build.c +++ b/xen/arch/x86/pv/dom0_build.c @@ -300,7 +300,6 @@ int __init dom0_construct_pv(struct doma struct page_info *page = NULL; start_info_t *si; struct vcpu *v = d->vcpu[0]; - unsigned long long value; void *image_base = bootstrap_map(image); unsigned long image_len = image->mod_end; void *image_start = image_base + image_headroom; @@ -357,27 +356,36 @@ int __init dom0_construct_pv(struct doma goto out; /* compatibility check */ + printk(" Xen kernel: 64-bit, lsb%s\n", + IS_ENABLED(CONFIG_PV32) ? ", compat32" : ""); compatible = 0; machine = elf_uval(&elf, elf.ehdr, e_machine); - printk(" Xen kernel: 64-bit, lsb, compat32\n"); - if ( elf_32bit(&elf) && parms.pae == XEN_PAE_BIMODAL ) - parms.pae = XEN_PAE_EXTCR3; - if ( elf_32bit(&elf) && parms.pae && machine == EM_386 ) + +#ifdef CONFIG_PV32 + if ( elf_32bit(&elf) ) { - if ( unlikely(rc = switch_compat(d)) ) + if ( parms.pae == XEN_PAE_BIMODAL ) + parms.pae = XEN_PAE_EXTCR3; + if ( parms.pae && machine == EM_386 ) { - printk("Dom0 failed to switch to compat: %d\n", rc); - return rc; - } + if ( unlikely(rc = switch_compat(d)) ) + { + printk("Dom0 failed to switch to compat: %d\n", rc); + return rc; + } - compatible = 1; + compatible = 1; + } } - if (elf_64bit(&elf) && machine == EM_X86_64) +#endif + + if ( elf_64bit(&elf) && machine == EM_X86_64 ) compatible = 1; - printk(" Dom0 kernel: %s%s, %s, paddr %#" PRIx64 " -> %#" PRIx64 "\n", - elf_64bit(&elf) ? "64-bit" : "32-bit", - parms.pae ? ", PAE" : "", - elf_msb(&elf) ? "msb" : "lsb", + + printk(" Dom0 kernel: %s-bit%s, %s, paddr %#" PRIx64 " -> %#" PRIx64 "\n", + elf_64bit(&elf) ? "64" : elf_32bit(&elf) ? "32" : "??", + parms.pae ? ", PAE" : "", + elf_msb(&elf) ? "msb" : "lsb", elf.pstart, elf.pend); if ( elf.bsd_symtab_pstart ) printk(" Dom0 symbol map %#" PRIx64 " -> %#" PRIx64 "\n", @@ -405,23 +413,28 @@ int __init dom0_construct_pv(struct doma if ( parms.pae == XEN_PAE_EXTCR3 ) set_bit(VMASST_TYPE_pae_extended_cr3, &d->vm_assist); - if ( !pv_shim && (parms.virt_hv_start_low != UNSET_ADDR) && - elf_32bit(&elf) ) +#ifdef CONFIG_PV32 + if ( elf_32bit(&elf) ) { - unsigned long mask = (1UL << L2_PAGETABLE_SHIFT) - 1; - value = (parms.virt_hv_start_low + mask) & ~mask; - BUG_ON(!is_pv_32bit_domain(d)); - if ( value > __HYPERVISOR_COMPAT_VIRT_START ) - panic("Domain 0 expects too high a hypervisor start address\n"); - HYPERVISOR_COMPAT_VIRT_START(d) = - max_t(unsigned int, m2p_compat_vstart, value); - } + if ( !pv_shim && (parms.virt_hv_start_low != UNSET_ADDR) ) + { + unsigned long mask = (1UL << L2_PAGETABLE_SHIFT) - 1; + unsigned long value = (parms.virt_hv_start_low + mask) & ~mask; - if ( (parms.p2m_base != UNSET_ADDR) && elf_32bit(&elf) ) - { - printk(XENLOG_WARNING "P2M table base ignored\n"); - parms.p2m_base = UNSET_ADDR; + BUG_ON(!is_pv_32bit_domain(d)); + if ( value > __HYPERVISOR_COMPAT_VIRT_START ) + panic("Domain 0 expects too high a hypervisor start address\n"); + HYPERVISOR_COMPAT_VIRT_START(d) = + max_t(unsigned int, m2p_compat_vstart, value); + } + + if ( parms.p2m_base != UNSET_ADDR ) + { + printk(XENLOG_WARNING "P2M table base ignored\n"); + parms.p2m_base = UNSET_ADDR; + } } +#endif /* * Why do we need this? The number of page-table frames depends on the
Add #ifdef-s (the 2nd one will be needed in particular, to guard the uses of m2p_compat_vstart and HYPERVISOR_COMPAT_VIRT_START()) and fold duplicate uses of elf_32bit(). Also adjust what gets logged: Avoid "compat32" when support isn't built in, and don't assume ELF class <> ELFCLASS64 means ELFCLASS32. Signed-off-by: Jan Beulich <jbeulich@suse.com>