Tianyu Lan <ltyker...@gmail.com> writes:
> From: Tianyu Lan <tianyu....@microsoft.com>
>
> Hyper-V exposes GHCB page via SEV ES GHCB MSR for SNP guest
> to communicate with hypervisor. Map GHCB page for all
> cpus to read/write MSR register and submit hvcall request
> via GHCB. Hyper-V also exposes shared memory boundary via
> cpuid HYPERV_CPUID_ISOLATION_CONFIG and store it in the
> shared_gpa_boundary of ms_hyperv struct. This prepares
> to share memory with host for SNP guest.
>
It seems the patch could be split into two: per-cpu GHCB setup and
shared memory boundary setup as these changes seem to be independent.
> Signed-off-by: Tianyu Lan <tianyu....@microsoft.com>
> ---
> arch/x86/hyperv/hv_init.c | 52 +++++++++++++++++++++++++++++++---
> arch/x86/kernel/cpu/mshyperv.c | 2 ++
> include/asm-generic/mshyperv.h | 14 ++++++++-
> 3 files changed, 63 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
> index 0db5137d5b81..90e65fbf4c58 100644
> --- a/arch/x86/hyperv/hv_init.c
> +++ b/arch/x86/hyperv/hv_init.c
> @@ -82,6 +82,9 @@ static int hv_cpu_init(unsigned int cpu)
> struct hv_vp_assist_page **hvp = &hv_vp_assist_page[smp_processor_id()];
> void **input_arg;
> struct page *pg;
> + u64 ghcb_gpa;
> + void *ghcb_va;
> + void **ghcb_base;
>
> /* hv_cpu_init() can be called with IRQs disabled from hv_resume() */
> pg = alloc_pages(irqs_disabled() ? GFP_ATOMIC : GFP_KERNEL,
> hv_root_partition ? 1 : 0);
> @@ -128,6 +131,17 @@ static int hv_cpu_init(unsigned int cpu)
> wrmsrl(HV_X64_MSR_VP_ASSIST_PAGE, val);
> }
>
> + if (ms_hyperv.ghcb_base) {
> + rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
> +
> + ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
Do we actually need to do ioremap_cache() and not ioremap_uc() for GHCB?
(just wondering)
> + if (!ghcb_va)
> + return -ENOMEM;
> +
> + ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
> + *ghcb_base = ghcb_va;
> + }
> +
> return 0;
> }
>
> @@ -223,6 +237,7 @@ static int hv_cpu_die(unsigned int cpu)
> unsigned long flags;
> void **input_arg;
> void *pg;
> + void **ghcb_va = NULL;
>
> local_irq_save(flags);
> input_arg = (void **)this_cpu_ptr(hyperv_pcpu_input_arg);
> @@ -236,6 +251,13 @@ static int hv_cpu_die(unsigned int cpu)
> *output_arg = NULL;
> }
>
> + if (ms_hyperv.ghcb_base) {
> + ghcb_va = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
> + if (*ghcb_va)
> + iounmap(*ghcb_va);
> + *ghcb_va = NULL;
> + }
> +
> local_irq_restore(flags);
>
> free_pages((unsigned long)pg, hv_root_partition ? 1 : 0);
> @@ -372,6 +394,9 @@ void __init hyperv_init(void)
> u64 guest_id, required_msrs;
> union hv_x64_msr_hypercall_contents hypercall_msr;
> int cpuhp, i;
> + u64 ghcb_gpa;
> + void *ghcb_va;
> + void **ghcb_base;
>
> if (x86_hyper_type != X86_HYPER_MS_HYPERV)
> return;
> @@ -432,9 +457,24 @@ void __init hyperv_init(void)
> VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,
> VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
> __builtin_return_address(0));
> - if (hv_hypercall_pg == NULL) {
> - wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
> - goto remove_cpuhp_state;
> + if (hv_hypercall_pg == NULL)
> + goto clean_guest_os_id;
> +
> + if (hv_isolation_type_snp()) {
> + ms_hyperv.ghcb_base = alloc_percpu(void *);
> + if (!ms_hyperv.ghcb_base)
> + goto clean_guest_os_id;
> +
> + rdmsrl(MSR_AMD64_SEV_ES_GHCB, ghcb_gpa);
> + ghcb_va = ioremap_cache(ghcb_gpa, HV_HYP_PAGE_SIZE);
> + if (!ghcb_va) {
> + free_percpu(ms_hyperv.ghcb_base);
> + ms_hyperv.ghcb_base = NULL;
> + goto clean_guest_os_id;
> + }
> +
> + ghcb_base = (void **)this_cpu_ptr(ms_hyperv.ghcb_base);
> + *ghcb_base = ghcb_va;
> }
>
> rdmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
> @@ -499,7 +539,8 @@ void __init hyperv_init(void)
>
> return;
>
> -remove_cpuhp_state:
> +clean_guest_os_id:
> + wrmsrl(HV_X64_MSR_GUEST_OS_ID, 0);
> cpuhp_remove_state(cpuhp);
> free_vp_assist_page:
> kfree(hv_vp_assist_page);
> @@ -528,6 +569,9 @@ void hyperv_cleanup(void)
> */
> hv_hypercall_pg = NULL;
>
> + if (ms_hyperv.ghcb_base)
> + free_percpu(ms_hyperv.ghcb_base);
> +
> /* Reset the hypercall page */
> hypercall_msr.as_uint64 = 0;
> wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);
> diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> index 347c32eac8fd..d6c363456cbf 100644
> --- a/arch/x86/kernel/cpu/mshyperv.c
> +++ b/arch/x86/kernel/cpu/mshyperv.c
> @@ -330,6 +330,8 @@ static void __init ms_hyperv_init_platform(void)
> if (ms_hyperv.features_b & HV_ISOLATION) {
> ms_hyperv.isolation_config_a =
> cpuid_eax(HYPERV_CPUID_ISOLATION_CONFIG);
> ms_hyperv.isolation_config_b =
> cpuid_ebx(HYPERV_CPUID_ISOLATION_CONFIG);
> + ms_hyperv.shared_gpa_boundary =
> + (u64)1 << ms_hyperv.shared_gpa_boundary_bits;
>
> pr_info("Hyper-V: Isolation Config: Group A 0x%x, Group B
> 0x%x\n",
> ms_hyperv.isolation_config_a,
> ms_hyperv.isolation_config_b);
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index dff58a3db5d5..ad0e33776668 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -34,7 +34,19 @@ struct ms_hyperv_info {
> u32 max_vp_index;
> u32 max_lp_index;
> u32 isolation_config_a;
> - u32 isolation_config_b;
> + union
> + {
> + u32 isolation_config_b;;
> + struct {
> + u32 cvm_type : 4;
> + u32 Reserved11 : 1;
> + u32 shared_gpa_boundary_active : 1;
> + u32 shared_gpa_boundary_bits : 6;
> + u32 Reserved12 : 20;
> + };
> + };
> + void __percpu **ghcb_base;
> + u64 shared_gpa_boundary;
> };
> extern struct ms_hyperv_info ms_hyperv;
--
Vitaly
