Michael Kelley
2021-Feb-04 16:52 UTC
[PATCH v6 05/16] x86/hyperv: allocate output arg pages if required
From: Wei Liu <wei.liu at kernel.org> Sent: Wednesday, February 3, 2021 7:04 AM> > 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 at microsoft.com> > Co-Developed-by: Lillian Grassin-Drake <ligrassi at microsoft.com> > Signed-off-by: Wei Liu <wei.liu at kernel.org> > --- > v3: Fix hv_cpu_die to use free_pages. > v2: Address Vitaly's comments > --- > arch/x86/hyperv/hv_init.c | 35 ++++++++++++++++++++++++++++----- > arch/x86/include/asm/mshyperv.h | 1 + > 2 files changed, 31 insertions(+), 5 deletions(-) > > diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c > index e04d90af4c27..6f4cb40e53fe 100644 > --- a/arch/x86/hyperv/hv_init.c > +++ b/arch/x86/hyperv/hv_init.c > @@ -41,6 +41,9 @@ 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); > > @@ -73,12 +76,19 @@ 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); > > @@ -205,14 +215,23 @@ 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); > @@ -346,6 +365,12 @@ 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); > diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h > index ac2b0d110f03..62d9390f1ddf 100644 > --- a/arch/x86/include/asm/mshyperv.h > +++ b/arch/x86/include/asm/mshyperv.h > @@ -76,6 +76,7 @@ static inline void hv_disable_stimer0_percpu_irq(int irq) {} > #if IS_ENABLED(CONFIG_HYPERV) > 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) > { > -- > 2.20.1Reviewed-by: Michael Kelley <mikelley at microsoft.com>