From a24fef73edc75c7aff7dc2cbcc2ee6df9893a2eb Mon Sep 17 00:00:00 2001 From: Julien Grall Date: Mon, 17 May 2021 17:47:13 +0100 Subject: [PATCH 1/2] xen/arm: Create dom0less domUs earlier In a follow-up patch we will need to unallocate the boot modules before heap_init_late() is called. The modules will contain the domUs kernel and initramfs. Therefore Xen will need to create extra domUs (used by dom0less) before heap_init_late(). This has two consequences on dom0less: 1) Domains will not be unpaused as soon as they are created but once all have been created. However, Xen doesn't guarantee an order to unpause, so this is not something one could rely on. 2) The memory allocated for a domU will not be scrubbed anymore when an admin select bootscrub=on. This is not something we advertised, but if this is a concern we can introduce either force scrub for all domUs or a per-domain flag in the DT. The behavior for bootscrub=off and bootscrub=idle (default) has not changed. This is part of XSA-372 / CVE-2021-28693. Signed-off-by: Julien Grall Reviewed-by: Jan Beulich Reviewed-by: Stefano Stabellini Tested-by: Stefano Stabellini --- xen/arch/arm/domain_build.c | 6 +----- xen/arch/arm/setup.c | 14 +++++++------- xen/include/asm-arm/setup.h | 2 +- 3 files changed, 9 insertions(+), 13 deletions(-) diff --git a/xen/arch/arm/domain_build.c b/xen/arch/arm/domain_build.c index 282416e74da4..6c86d527810f 100644 --- a/xen/arch/arm/domain_build.c +++ b/xen/arch/arm/domain_build.c @@ -2521,8 +2521,6 @@ void __init create_domUs(void) if ( construct_domU(d, node) != 0 ) panic("Could not set up domain %s\n", dt_node_name(node)); - - domain_unpause_by_systemcontroller(d); } } @@ -2584,7 +2582,7 @@ static int __init construct_dom0(struct domain *d) return construct_domain(d, &kinfo); } -struct domain* __init create_dom0(void) +void __init create_dom0(void) { struct domain *dom0; struct xen_domctl_createdomain dom0_cfg = { @@ -2615,8 +2613,6 @@ struct domain* __init create_dom0(void) if ( construct_dom0(dom0) != 0) panic("Could not set up DOM0 guest OS\n"); - - return dom0; } /* diff --git a/xen/arch/arm/setup.c b/xen/arch/arm/setup.c index 00aad1c194b9..e17532c132cf 100644 --- a/xen/arch/arm/setup.c +++ b/xen/arch/arm/setup.c @@ -836,7 +836,7 @@ void __init start_xen(unsigned long boot_phys_offset, int cpus, i; const char *cmdline; struct bootmodule *xen_bootmodule; - struct domain *dom0 = NULL; + struct domain *d; int rc; dcache_line_bytes = read_dcache_line_bytes(); @@ -992,10 +992,13 @@ void __init start_xen(unsigned long boot_phys_offset, /* Create initial domain 0. */ if ( !is_dom0less_mode() ) - dom0 = create_dom0(); + create_dom0(); else printk(XENLOG_INFO "Xen dom0less mode detected\n"); + if ( acpi_disabled ) + create_domUs(); + heap_init_late(); init_trace_bufs(); @@ -1009,11 +1012,8 @@ void __init start_xen(unsigned long boot_phys_offset, system_state = SYS_STATE_active; - if ( acpi_disabled ) - create_domUs(); - - if ( dom0 ) - domain_unpause_by_systemcontroller(dom0); + for_each_domain( d ) + domain_unpause_by_systemcontroller(d); /* Switch on to the dynamically allocated stack for the idle vcpu * since the static one we're running on is about to be freed. */ diff --git a/xen/include/asm-arm/setup.h b/xen/include/asm-arm/setup.h index 528324401511..c4b6af602995 100644 --- a/xen/include/asm-arm/setup.h +++ b/xen/include/asm-arm/setup.h @@ -94,7 +94,7 @@ void acpi_create_efi_mmap_table(struct domain *d, int acpi_make_efi_nodes(void *fdt, struct membank tbl_add[]); void create_domUs(void); -struct domain* create_dom0(void); +void create_dom0(void); void discard_initial_modules(void); void fw_unreserved_regions(paddr_t s, paddr_t e, -- 2.17.1