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x86/hyperv: allocate output arg pages if required

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When Linux runs as the root partition, it will need to make hypercalls
which return data from the hypervisor.

Allocate pages for storing results when Linux runs as the root
partition.

Signed-off-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Co-Developed-by: Lillian Grassin-Drake <ligrassi@microsoft.com>
Signed-off-by: Wei Liu <wei.liu@kernel.org>
Reviewed-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20210203150435.27941-6-wei.liu@kernel.org
This commit is contained in:
Wei Liu 2021-02-03 15:04:24 +00:00
parent 7d4163c831
commit 5d0f077e0f
2 changed files with 31 additions and 5 deletions
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35
arch/x86/hyperv/hv_init.c
View File

@ -45,6 +45,9 @@ EXPORT_SYMBOL_GPL(hv_vp_assist_page);
void __percpu **hyperv_pcpu_input_arg;
EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
void __percpu **hyperv_pcpu_output_arg;
EXPORT_SYMBOL_GPL(hyperv_pcpu_output_arg);
u32 hv_max_vp_index;
EXPORT_SYMBOL_GPL(hv_max_vp_index);
@ -77,12 +80,19 @@ static int hv_cpu_init(unsigned int cpu)
void **input_arg;
struct page *pg;
input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
/* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
pg = alloc_page(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL);
pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL, hv_root_partition ? 1 : 0);
if (unlikely(!pg))
return -ENOMEM;
input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
*input_arg = page_address(pg);
if (hv_root_partition) {
void **output_arg;
output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
*output_arg = page_address(pg + 1);
}
hv_get_vp_index(msr_vp_index);
@ -209,14 +219,23 @@ static int hv_cpu_die(unsigned int cpu)
unsigned int new_cpu;
unsigned long flags;
void **input_arg;
void *input_pg = NULL;
void *pg;
local_irq_save(flags);
input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
input_pg = *input_arg;
pg = *input_arg;
*input_arg = NULL;
if (hv_root_partition) {
void **output_arg;
output_arg = (void **)this_cpu_ptr(hyperv_pcpu_output_arg);
*output_arg = NULL;
}
local_irq_restore(flags);
free_page((unsigned long)input_pg);
free_pages((unsigned long)pg, hv_root_partition ? 1 : 0);
if (hv_vp_assist_page && hv_vp_assist_page[cpu])
wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, 0);
@ -369,6 +388,12 @@ void __init hyperv_init(void)
BUG_ON(hyperv_pcpu_input_arg == NULL);
/* Allocate the per-CPU state for output arg for root */
if (hv_root_partition) {
hyperv_pcpu_output_arg = alloc_percpu(void *);
BUG_ON(hyperv_pcpu_output_arg == NULL);
}
/* Allocate percpu VP index */
hv_vp_index = kmalloc_array(num_possible_cpus(), sizeof(*hv_vp_index),
GFP_KERNEL);

1
arch/x86/include/asm/mshyperv.h
View File

@ -78,6 +78,7 @@ extern int hyperv_init_cpuhp;
extern void *hv_hypercall_pg;
extern void __percpu **hyperv_pcpu_input_arg;
extern void __percpu **hyperv_pcpu_output_arg;
static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
{