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x86/hyperv: handling hypercall page setup for root

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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: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Signed-off-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Sunil Muthuswamy <sunilmut@microsoft.com>
Co-Developed-by: Nuno Das Neves <nunodasneves@linux.microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-8-wei.liu@kernel.org
This commit is contained in:
Wei Liu 2021-02-03 15:04:26 +00:00
parent 99a0f46af6
commit 80f73c9f74
1 changed files with 34 additions and 3 deletions
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37
arch/x86/hyperv/hv_init.c
View file

@ -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;
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;
/*
* 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);