When Linux is running as the root partition, the hypercall page will have already been setup by Hyper-V. Copy the content over to the allocated page.
The suspend, resume and cleanup paths remain untouched because they are not supported in this setup yet. Signed-off-by: Lillian Grassin-Drake <[email protected]> Signed-off-by: Sunil Muthuswamy <[email protected]> Signed-off-by: Nuno Das Neves <[email protected]> Co-Developed-by: Lillian Grassin-Drake <[email protected]> Co-Developed-by: Sunil Muthuswamy <[email protected]> Co-Developed-by: Nuno Das Neves <[email protected]> Signed-off-by: Wei Liu <[email protected]> --- arch/x86/hyperv/hv_init.c | 26 ++++++++++++++++++++++++-- 1 file changed, 24 insertions(+), 2 deletions(-) diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c index 0eec1ed32023..26233aebc86c 100644 --- a/arch/x86/hyperv/hv_init.c +++ b/arch/x86/hyperv/hv_init.c @@ -25,6 +25,7 @@ #include <linux/cpuhotplug.h> #include <linux/syscore_ops.h> #include <clocksource/hyperv_timer.h> +#include <linux/highmem.h> /* Is Linux running as the root partition? */ bool hv_root_partition; @@ -448,8 +449,29 @@ void __init hyperv_init(void) rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); hypercall_msr.enable = 1; - hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); - wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); + + if (hv_root_partition) { + struct page *pg; + void *src, *dst; + + /* + * Order is important here. We must enable the hypercall page + * so it is populated with code, then copy the code to an + * executable page. + */ + wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); + + pg = vmalloc_to_page(hv_hypercall_pg); + dst = kmap(pg); + src = memremap(hypercall_msr.guest_physical_address << PAGE_SHIFT, PAGE_SIZE, + MEMREMAP_WB); + memcpy(dst, src, PAGE_SIZE); + memunmap(src); + kunmap(pg); + } else { + hypercall_msr.guest_physical_address = vmalloc_to_pfn(hv_hypercall_pg); + wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64); + } /* * Ignore any errors in setting up stimer clockevents -- 2.20.1
