From: Mike Larkin Subject: Re: AMD SEV: confidential autoconf whitelist To: tech@openbsd.org Date: Sat, 13 Sep 2025 07:10:00 -0700 On Tue, Sep 09, 2025 at 11:42:38AM +0200, Hans-Jörg Höxer wrote: > Hi, > > this is an updated diff that works well on vmd/vmm and linux/kvm hosts > with SEV-ES enabled guests. > > The previous discussion raised some questions, thanks for your input! > All in all we came to the conclusion to proceed with this approach. > > ok? > what was the final decision here? -ml > Take care, > HJ. > ------------------------------------------------------------------------- > > commit 576036aa72fef155f1584690fab5bdfe018672b8 > Author: Hans-Joerg Hoexer > Date: Sat Aug 2 12:58:50 2025 +0200 > > Whitelist devices in cfdrive for use when SEV is enabled > > Skip devices, that are not flagged for use with SEV. Hook into > config_search() and isascan(). > > diff --git a/sys/arch/amd64/amd64/bios.c b/sys/arch/amd64/amd64/bios.c > index 3a264d09d5b..15dec870ba6 100644 > --- a/sys/arch/amd64/amd64/bios.c > +++ b/sys/arch/amd64/amd64/bios.c > @@ -50,7 +50,7 @@ const struct cfattach bios_ca = { > }; > > struct cfdriver bios_cd = { > - NULL, "bios", DV_DULL > + NULL, "bios", DV_DULL, CD_COCOVM > }; > > struct smbios_entry smbios_entry; > diff --git a/sys/arch/amd64/amd64/cpu.c b/sys/arch/amd64/amd64/cpu.c > index 1287c610344..b8ad479cefa 100644 > --- a/sys/arch/amd64/amd64/cpu.c > +++ b/sys/arch/amd64/amd64/cpu.c > @@ -445,7 +445,7 @@ const struct cfattach cpu_ca = { > }; > > struct cfdriver cpu_cd = { > - NULL, "cpu", DV_DULL > + NULL, "cpu", DV_DULL, CD_COCOVM > }; > > /* > diff --git a/sys/arch/amd64/amd64/ioapic.c b/sys/arch/amd64/amd64/ioapic.c > index 9989fdfeb29..40af6c4154d 100644 > --- a/sys/arch/amd64/amd64/ioapic.c > +++ b/sys/arch/amd64/amd64/ioapic.c > @@ -231,7 +231,7 @@ const struct cfattach ioapic_ca = { > }; > > struct cfdriver ioapic_cd = { > - NULL, "ioapic", DV_DULL > + NULL, "ioapic", DV_DULL, CD_COCOVM > }; > > int > diff --git a/sys/arch/amd64/amd64/machdep.c b/sys/arch/amd64/amd64/machdep.c > index 3462ac54559..7c540328d98 100644 > --- a/sys/arch/amd64/amd64/machdep.c > +++ b/sys/arch/amd64/amd64/machdep.c > @@ -1474,6 +1474,8 @@ init_x86_64(paddr_t first_avail) > cpu_init_early_vctrap(first_avail); > first_avail += 2 * NBPG; > } > + if (ISSET(cpu_sev_guestmode, SEV_STAT_ENABLED)) > + boothowto |= RB_COCOVM; > > /* > * locore0 mapped 3 pages for use before the pmap is initialized > diff --git a/sys/arch/amd64/amd64/mainbus.c b/sys/arch/amd64/amd64/mainbus.c > index 030f0b1212f..f77a67f5517 100644 > --- a/sys/arch/amd64/amd64/mainbus.c > +++ b/sys/arch/amd64/amd64/mainbus.c > @@ -83,7 +83,7 @@ const struct cfattach mainbus_ca = { > }; > > struct cfdriver mainbus_cd = { > - NULL, "mainbus", DV_DULL > + NULL, "mainbus", DV_DULL, CD_COCOVM > }; > > int mainbus_print(void *, const char *); > diff --git a/sys/arch/amd64/pci/acpipci.c b/sys/arch/amd64/pci/acpipci.c > index 5b07e2d3aba..81d8ad3ced0 100644 > --- a/sys/arch/amd64/pci/acpipci.c > +++ b/sys/arch/amd64/pci/acpipci.c > @@ -76,7 +76,7 @@ const struct cfattach acpipci_ca = { > }; > > struct cfdriver acpipci_cd = { > - NULL, "acpipci", DV_DULL > + NULL, "acpipci", DV_DULL, CD_COCOVM > }; > > const char *acpipci_hids[] = { > diff --git a/sys/arch/amd64/pci/pchb.c b/sys/arch/amd64/pci/pchb.c > index 9b10011e2db..eb06df06b19 100644 > --- a/sys/arch/amd64/pci/pchb.c > +++ b/sys/arch/amd64/pci/pchb.c > @@ -122,7 +122,7 @@ const struct cfattach pchb_ca = { > }; > > struct cfdriver pchb_cd = { > - NULL, "pchb", DV_DULL > + NULL, "pchb", DV_DULL, CD_COCOVM > }; > > int pchb_print(void *, const char *); > diff --git a/sys/dev/acpi/acpi.c b/sys/dev/acpi/acpi.c > index 7bcf56cab49..bb3645528c9 100644 > --- a/sys/dev/acpi/acpi.c > +++ b/sys/dev/acpi/acpi.c > @@ -184,7 +184,7 @@ struct acpi_softc *acpi_softc; > extern struct aml_node aml_root; > > struct cfdriver acpi_cd = { > - NULL, "acpi", DV_DULL > + NULL, "acpi", DV_DULL, CD_COCOVM > }; > > uint8_t > diff --git a/sys/dev/acpi/acpicmos.c b/sys/dev/acpi/acpicmos.c > index 6e424e26530..068787c1922 100644 > --- a/sys/dev/acpi/acpicmos.c > +++ b/sys/dev/acpi/acpicmos.c > @@ -37,7 +37,7 @@ const struct cfattach acpicmos_ca = { > }; > > struct cfdriver acpicmos_cd = { > - NULL, "acpicmos", DV_DULL > + NULL, "acpicmos", DV_DULL, CD_COCOVM > }; > > const char *acpicmos_hids[] = { > diff --git a/sys/dev/acpi/acpicpu_x86.c b/sys/dev/acpi/acpicpu_x86.c > index 15f0ceeaeae..a5ddc55b1b3 100644 > --- a/sys/dev/acpi/acpicpu_x86.c > +++ b/sys/dev/acpi/acpicpu_x86.c > @@ -183,7 +183,7 @@ const struct cfattach acpicpu_ca = { > }; > > struct cfdriver acpicpu_cd = { > - NULL, "acpicpu", DV_DULL > + NULL, "acpicpu", DV_DULL, CD_COCOVM > }; > > const char *acpicpu_hids[] = { > diff --git a/sys/dev/acpi/acpihpet.c b/sys/dev/acpi/acpihpet.c > index dd992132678..dd25309c1c5 100644 > --- a/sys/dev/acpi/acpihpet.c > +++ b/sys/dev/acpi/acpihpet.c > @@ -79,7 +79,7 @@ const struct cfattach acpihpet_ca = { > }; > > struct cfdriver acpihpet_cd = { > - NULL, "acpihpet", DV_DULL > + NULL, "acpihpet", DV_DULL, CD_COCOVM > }; > > uint64_t > diff --git a/sys/dev/acpi/acpimadt.c b/sys/dev/acpi/acpimadt.c > index 3faed32b355..6359ffd925b 100644 > --- a/sys/dev/acpi/acpimadt.c > +++ b/sys/dev/acpi/acpimadt.c > @@ -48,7 +48,7 @@ const struct cfattach acpimadt_ca = { > }; > > struct cfdriver acpimadt_cd = { > - NULL, "acpimadt", DV_DULL > + NULL, "acpimadt", DV_DULL, CD_COCOVM > }; > > int acpimadt_validate(struct acpi_madt *); > diff --git a/sys/dev/acpi/acpimcfg.c b/sys/dev/acpi/acpimcfg.c > index f3e520882aa..b7df8a297a0 100644 > --- a/sys/dev/acpi/acpimcfg.c > +++ b/sys/dev/acpi/acpimcfg.c > @@ -31,7 +31,7 @@ const struct cfattach acpimcfg_ca = { > }; > > struct cfdriver acpimcfg_cd = { > - NULL, "acpimcfg", DV_DULL > + NULL, "acpimcfg", DV_DULL, CD_COCOVM > }; > > int > diff --git a/sys/dev/acpi/acpiprt.c b/sys/dev/acpi/acpiprt.c > index 39de79dcfca..1011ec68600 100644 > --- a/sys/dev/acpi/acpiprt.c > +++ b/sys/dev/acpi/acpiprt.c > @@ -77,7 +77,7 @@ const struct cfattach acpiprt_ca = { > }; > > struct cfdriver acpiprt_cd = { > - NULL, "acpiprt", DV_DULL > + NULL, "acpiprt", DV_DULL, CD_COCOVM > }; > > void acpiprt_prt_add(struct acpiprt_softc *, struct aml_value *); > diff --git a/sys/dev/acpi/acpitimer.c b/sys/dev/acpi/acpitimer.c > index 11a8b9eccf3..498146a592e 100644 > --- a/sys/dev/acpi/acpitimer.c > +++ b/sys/dev/acpi/acpitimer.c > @@ -55,7 +55,7 @@ const struct cfattach acpitimer_ca = { > }; > > struct cfdriver acpitimer_cd = { > - NULL, "acpitimer", DV_DULL > + NULL, "acpitimer", DV_DULL, CD_COCOVM > }; > > int > diff --git a/sys/dev/efi/efi.c b/sys/dev/efi/efi.c > index 43a774253fa..e600a3b1e47 100644 > --- a/sys/dev/efi/efi.c > +++ b/sys/dev/efi/efi.c > @@ -24,7 +24,7 @@ > #include > > struct cfdriver efi_cd = { > - NULL, "efi", DV_DULL > + NULL, "efi", DV_DULL, CD_COCOVM > }; > > int efiioc_get_table(struct efi_softc *sc, void *); > diff --git a/sys/dev/ic/com.c b/sys/dev/ic/com.c > index dd45e3c901c..da29f82243b 100644 > --- a/sys/dev/ic/com.c > +++ b/sys/dev/ic/com.c > @@ -96,7 +96,7 @@ void compwroff(struct com_softc *); > void cominit(bus_space_tag_t, bus_space_handle_t, int, int); > > struct cfdriver com_cd = { > - NULL, "com", DV_TTY > + NULL, "com", DV_TTY, CD_COCOVM > }; > > int comdefaultrate = TTYDEF_SPEED; > diff --git a/sys/dev/isa/isa.c b/sys/dev/isa/isa.c > index 2d11dc33a84..2a799f8a82a 100644 > --- a/sys/dev/isa/isa.c > +++ b/sys/dev/isa/isa.c > @@ -62,6 +62,7 @@ > #include > #include > #include > +#include > > #include > #include > @@ -84,7 +85,7 @@ const struct cfattach isa_ca = { > }; > > struct cfdriver isa_cd = { > - NULL, "isa", DV_DULL, CD_INDIRECT > + NULL, "isa", DV_DULL, CD_INDIRECT | CD_COCOVM > }; > > int > @@ -218,6 +219,10 @@ isascan(struct device *parent, void *match) > ia.ipa_ndrq = 2; > ia.ia_delaybah = sc->sc_delaybah; > > + if (ISSET(boothowto, RB_COCOVM) && > + !ISSET(cf->cf_driver->cd_mode, CD_COCOVM)) > + return; > + > if (cf->cf_fstate == FSTATE_STAR) { > struct isa_attach_args ia2 = ia; > > diff --git a/sys/dev/pci/pci.c b/sys/dev/pci/pci.c > index c0376842914..d7601dd976e 100644 > --- a/sys/dev/pci/pci.c > +++ b/sys/dev/pci/pci.c > @@ -90,7 +90,7 @@ const struct cfattach pci_ca = { > }; > > struct cfdriver pci_cd = { > - NULL, "pci", DV_DULL > + NULL, "pci", DV_DULL, CD_COCOVM > }; > > int pci_ndomains; > diff --git a/sys/dev/pci/ppb.c b/sys/dev/pci/ppb.c > index cf7cb120cc1..f6ab05f9168 100644 > --- a/sys/dev/pci/ppb.c > +++ b/sys/dev/pci/ppb.c > @@ -113,7 +113,7 @@ const struct cfattach ppb_ca = { > }; > > struct cfdriver ppb_cd = { > - NULL, "ppb", DV_DULL > + NULL, "ppb", DV_DULL, CD_COCOVM > }; > > void ppb_alloc_busrange(struct ppb_softc *, struct pci_attach_args *, > diff --git a/sys/dev/pv/if_vio.c b/sys/dev/pv/if_vio.c > index a94945a8ea0..458f98c6a7a 100644 > --- a/sys/dev/pv/if_vio.c > +++ b/sys/dev/pv/if_vio.c > @@ -382,7 +382,7 @@ const struct cfattach vio_ca = { > }; > > struct cfdriver vio_cd = { > - NULL, "vio", DV_IFNET > + NULL, "vio", DV_IFNET, CD_COCOVM > }; > > int > diff --git a/sys/dev/pv/pvbus.c b/sys/dev/pv/pvbus.c > index 165fcc9fbff..a482072de4b 100644 > --- a/sys/dev/pv/pvbus.c > +++ b/sys/dev/pv/pvbus.c > @@ -68,7 +68,8 @@ const struct cfattach pvbus_ca = { > struct cfdriver pvbus_cd = { > NULL, > "pvbus", > - DV_DULL > + DV_DULL, > + CD_COCOVM > }; > > struct pvbus_type { > diff --git a/sys/dev/pv/pvclock.c b/sys/dev/pv/pvclock.c > index 89eff0ce248..fd69960ddda 100644 > --- a/sys/dev/pv/pvclock.c > +++ b/sys/dev/pv/pvclock.c > @@ -125,7 +125,8 @@ const struct cfattach pvclock_ca = { > struct cfdriver pvclock_cd = { > NULL, > "pvclock", > - DV_DULL > + DV_DULL, > + CD_COCOVM > }; > > struct timecounter pvclock_timecounter = { > diff --git a/sys/dev/pv/vioblk.c b/sys/dev/pv/vioblk.c > index 7f7a518332f..761ce73a847 100644 > --- a/sys/dev/pv/vioblk.c > +++ b/sys/dev/pv/vioblk.c > @@ -146,7 +146,7 @@ const struct cfattach vioblk_ca = { > }; > > struct cfdriver vioblk_cd = { > - NULL, "vioblk", DV_DULL > + NULL, "vioblk", DV_DULL, CD_COCOVM > }; > > const struct scsi_adapter vioblk_switch = { > diff --git a/sys/dev/pv/viocon.c b/sys/dev/pv/viocon.c > index 95a1e875579..1d24074c54d 100644 > --- a/sys/dev/pv/viocon.c > +++ b/sys/dev/pv/viocon.c > @@ -144,7 +144,7 @@ const struct cfattach viocon_ca = { > }; > > struct cfdriver viocon_cd = { > - NULL, "viocon", DV_TTY > + NULL, "viocon", DV_TTY, CD_COCOVM > }; > > static inline struct viocon_softc * > diff --git a/sys/dev/pv/viornd.c b/sys/dev/pv/viornd.c > index 484f7ce1be0..9eeb6115f3e 100644 > --- a/sys/dev/pv/viornd.c > +++ b/sys/dev/pv/viornd.c > @@ -66,7 +66,7 @@ const struct cfattach viornd_ca = { > }; > > struct cfdriver viornd_cd = { > - NULL, "viornd", DV_DULL > + NULL, "viornd", DV_DULL, CD_COCOVM > }; > > int > diff --git a/sys/dev/pv/virtio.c b/sys/dev/pv/virtio.c > index ac0432dc9f9..4a8d140f797 100644 > --- a/sys/dev/pv/virtio.c > +++ b/sys/dev/pv/virtio.c > @@ -48,7 +48,7 @@ void vq_free_entry(struct virtqueue *, struct vq_entry *); > struct vq_entry *vq_alloc_entry(struct virtqueue *); > > struct cfdriver virtio_cd = { > - NULL, "virtio", DV_DULL > + NULL, "virtio", DV_DULL, CD_COCOVM > }; > > static const char * const virtio_device_name[] = { > diff --git a/sys/dev/pv/vmmci.c b/sys/dev/pv/vmmci.c > index 984626393cd..18930c62766 100644 > --- a/sys/dev/pv/vmmci.c > +++ b/sys/dev/pv/vmmci.c > @@ -72,7 +72,7 @@ const struct cfattach vmmci_ca = { > #define VMMCI_F_SYNCRTC (1ULL<<2) > > struct cfdriver vmmci_cd = { > - NULL, "vmmci", DV_DULL > + NULL, "vmmci", DV_DULL, CD_COCOVM > }; > > int > diff --git a/sys/dev/softraid.c b/sys/dev/softraid.c > index c10ebeaaa93..41929692397 100644 > --- a/sys/dev/softraid.c > +++ b/sys/dev/softraid.c > @@ -88,7 +88,7 @@ const struct cfattach softraid_ca = { > }; > > struct cfdriver softraid_cd = { > - NULL, "softraid", DV_DULL > + NULL, "softraid", DV_DULL, CD_COCOVM > }; > > /* scsi & discipline */ > diff --git a/sys/dev/vscsi.c b/sys/dev/vscsi.c > index 31885a6b9c9..2e2deb25b1f 100644 > --- a/sys/dev/vscsi.c > +++ b/sys/dev/vscsi.c > @@ -89,7 +89,8 @@ const struct cfattach vscsi_ca = { > struct cfdriver vscsi_cd = { > NULL, > "vscsi", > - DV_DULL > + DV_DULL, > + CD_COCOVM > }; > > void vscsi_cmd(struct scsi_xfer *); > diff --git a/sys/kern/subr_autoconf.c b/sys/kern/subr_autoconf.c > index 41633140dc6..eec9eef15ce 100644 > --- a/sys/kern/subr_autoconf.c > +++ b/sys/kern/subr_autoconf.c > @@ -216,6 +216,9 @@ config_search(cfmatch_t fn, struct device *parent, void *aux) > if (cf->cf_driver->cd_class == DV_TAPE) > continue; > } > + if (ISSET(boothowto, RB_COCOVM) && > + !ISSET(cf->cf_driver->cd_mode, CD_COCOVM)) > + continue; > for (p = cf->cf_parents; *p >= 0; p++) > if (parent->dv_cfdata == &cfdata[*p]) > mapply(&m, cf); > diff --git a/sys/scsi/mpath.c b/sys/scsi/mpath.c > index c94a4ff5cf7..090c78c35f1 100644 > --- a/sys/scsi/mpath.c > +++ b/sys/scsi/mpath.c > @@ -79,7 +79,8 @@ const struct cfattach mpath_ca = { > struct cfdriver mpath_cd = { > NULL, > "mpath", > - DV_DULL > + DV_DULL, > + CD_COCOVM > }; > > void mpath_cmd(struct scsi_xfer *); > diff --git a/sys/scsi/scsiconf.c b/sys/scsi/scsiconf.c > index 495020a23a3..2f9ab1b15d0 100644 > --- a/sys/scsi/scsiconf.c > +++ b/sys/scsi/scsiconf.c > @@ -102,7 +102,7 @@ const struct cfattach scsibus_ca = { > }; > > struct cfdriver scsibus_cd = { > - NULL, "scsibus", DV_DULL > + NULL, "scsibus", DV_DULL, CD_COCOVM > }; > > struct scsi_quirk_inquiry_pattern { > diff --git a/sys/scsi/sd.c b/sys/scsi/sd.c > index 9b02314c679..085ad01cd78 100644 > --- a/sys/scsi/sd.c > +++ b/sys/scsi/sd.c > @@ -116,7 +116,7 @@ const struct cfattach sd_ca = { > }; > > struct cfdriver sd_cd = { > - NULL, "sd", DV_DISK > + NULL, "sd", DV_DISK, CD_COCOVM > }; > > const struct scsi_inquiry_pattern sd_patterns[] = { > diff --git a/sys/sys/device.h b/sys/sys/device.h > index 5dccec16cf8..2c4171017ec 100644 > --- a/sys/sys/device.h > +++ b/sys/sys/device.h > @@ -139,6 +139,7 @@ struct cfattach { > /* For cd_mode, below */ > #define CD_INDIRECT 1 > #define CD_SKIPHIBERNATE 2 > +#define CD_COCOVM 4 > > struct cfdriver { > void **cd_devs; /* devices found */ > diff --git a/sys/sys/reboot.h b/sys/sys/reboot.h > index bf3e7f82680..1998f21691b 100644 > --- a/sys/sys/reboot.h > +++ b/sys/sys/reboot.h > @@ -59,6 +59,7 @@ > #define RB_RESET 0x08000 /* just reset, no cleanup */ > #define RB_GOODRANDOM 0x10000 /* excellent random seed loaded */ > #define RB_UNHIBERNATE 0x20000 /* unhibernate */ > +#define RB_COCOVM 0x40000 /* VM booting with SEV enabled */ > > /* > * Constants for converting boot-style device number to type,