Commit 80f73c9f authored by Wei Liu's avatar Wei Liu
Browse files

x86/hyperv: handling hypercall page setup for root 



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.

Add checks to hv_suspend & co to bail early because they are not
supported in this setup yet.

Signed-off-by: default avatarLillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: default avatarSunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: default avatarNuno Das Neves <nunodasneves@linux.microsoft.com>
Co-Developed-by: default avatarLillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: default avatarSunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: default avatarNuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-8-wei.liu@kernel.org
parent 99a0f46a

arch/x86/hyperv/hv_init.c

+34 −3
Original line number Diff line number Diff line
@@ -27,6 +27,7 @@ 
#include <linux/cpuhotplug.h>

#include <linux/syscore_ops.h>

#include <clocksource/hyperv_timer.h>

#include <linux/highmem.h>



int hyperv_init_cpuhp;

u64 hv_current_partition_id = ~0ull;
@@ -286,6 +287,9 @@ static int hv_suspend(void) 
	union hv_x64_msr_hypercall_contents hypercall_msr;

	int ret;



	if (hv_root_partition)

		return -EPERM;



	/*

	 * Reset the hypercall page as it is going to be invalidated

	 * accross hibernation. Setting hv_hypercall_pg to NULL ensures
@@ -454,8 +458,35 @@ void __init hyperv_init(void) 


	rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

	hypercall_msr.enable = 1;



	if (hv_root_partition) {

		struct page *pg;

		void *src, *dst;



		/*

		 * For the root partition, the hypervisor will set up its

		 * hypercall page. The hypervisor guarantees it will not show

		 * up in the root's address space. The root can't change the

		 * location of the hypercall page.

		 *

		 * 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);

		BUG_ON(!(src && dst));

		memcpy(dst, src, HV_HYP_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);

	}



	/*

	 * hyperv_init() is called before LAPIC is initialized: see
@@ -604,7 +635,7 @@ EXPORT_SYMBOL_GPL(hv_is_hyperv_initialized); 


bool hv_is_hibernation_supported(void)

{

	return acpi_sleep_state_supported(ACPI_STATE_S4);

	return !hv_root_partition && acpi_sleep_state_supported(ACPI_STATE_S4);

}

EXPORT_SYMBOL_GPL(hv_is_hibernation_supported);