diff options
Diffstat (limited to 'arch/x86/hyperv/hv_vtl.c')
| -rw-r--r-- | arch/x86/hyperv/hv_vtl.c | 40 |
1 files changed, 38 insertions, 2 deletions
diff --git a/arch/x86/hyperv/hv_vtl.c b/arch/x86/hyperv/hv_vtl.c index 4e1b1e3b5658..4580936dcb03 100644 --- a/arch/x86/hyperv/hv_vtl.c +++ b/arch/x86/hyperv/hv_vtl.c @@ -11,7 +11,9 @@ #include <asm/desc.h> #include <asm/i8259.h> #include <asm/mshyperv.h> +#include <asm/msr.h> #include <asm/realmode.h> +#include <asm/reboot.h> #include <../kernel/smpboot.h> extern struct boot_params boot_params; @@ -22,6 +24,36 @@ static bool __init hv_vtl_msi_ext_dest_id(void) return true; } +/* + * The `native_machine_emergency_restart` function from `reboot.c` writes + * to the physical address 0x472 to indicate the type of reboot for the + * firmware. We cannot have that in VSM as the memory composition might + * be more generic, and such write effectively corrupts the memory thus + * making diagnostics harder at the very least. + */ +static void __noreturn hv_vtl_emergency_restart(void) +{ + /* + * Cause a triple fault and the immediate reset. Here the code does not run + * on the top of any firmware, whereby cannot reach out to its services. + * The inifinite loop is for the improbable case that the triple fault does + * not work and have to preserve the state intact for debugging. + */ + for (;;) { + idt_invalidate(); + __asm__ __volatile__("int3"); + } +} + +/* + * The only way to restart in the VTL mode is to triple fault as the kernel runs + * as firmware. + */ +static void __noreturn hv_vtl_restart(char __maybe_unused *cmd) +{ + hv_vtl_emergency_restart(); +} + void __init hv_vtl_init_platform(void) { pr_info("Linux runs in Hyper-V Virtual Trust Level\n"); @@ -30,6 +62,7 @@ void __init hv_vtl_init_platform(void) x86_platform.realmode_init = x86_init_noop; x86_init.irqs.pre_vector_init = x86_init_noop; x86_init.timers.timer_init = x86_init_noop; + x86_init.resources.probe_roms = x86_init_noop; /* Avoid searching for BIOS MP tables */ x86_init.mpparse.find_mptable = x86_init_noop; @@ -117,11 +150,11 @@ static int hv_vtl_bringup_vcpu(u32 target_vp_index, int cpu, u64 eip_ignored) input->vp_context.rip = rip; input->vp_context.rsp = rsp; input->vp_context.rflags = 0x0000000000000002; - input->vp_context.efer = __rdmsr(MSR_EFER); + input->vp_context.efer = native_rdmsrq(MSR_EFER); input->vp_context.cr0 = native_read_cr0(); input->vp_context.cr3 = __native_read_cr3(); input->vp_context.cr4 = native_read_cr4(); - input->vp_context.msr_cr_pat = __rdmsr(MSR_IA32_CR_PAT); + input->vp_context.msr_cr_pat = native_rdmsrq(MSR_IA32_CR_PAT); input->vp_context.idtr.limit = idt_ptr.size; input->vp_context.idtr.base = idt_ptr.address; input->vp_context.gdtr.limit = gdt_ptr.size; @@ -235,6 +268,9 @@ static int hv_vtl_wakeup_secondary_cpu(u32 apicid, unsigned long start_eip) int __init hv_vtl_early_init(void) { + machine_ops.emergency_restart = hv_vtl_emergency_restart; + machine_ops.restart = hv_vtl_restart; + /* * `boot_cpu_has` returns the runtime feature support, * and here is the earliest it can be used. |