Commit d6e0228d authored by Dexuan Cui's avatar Dexuan Cui Committed by Wei Liu
Browse files

x86/hyperv: Support hypercalls for fully enlightened TDX guests 



A fully enlightened TDX guest on Hyper-V (i.e. without the paravisor) only
uses the GHCI call rather than hv_hypercall_pg. Do not initialize
hypercall_pg for such a guest.

In hv_common_cpu_init(), the hyperv_pcpu_input_arg page needs to be
decrypted in such a guest.

Reviewed-by: default avatarKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Reviewed-by: default avatarMichael Kelley <mikelley@microsoft.com>
Reviewed-by: default avatarTianyu Lan <tiala@microsoft.com>
Signed-off-by: default avatarDexuan Cui <decui@microsoft.com>
Signed-off-by: default avatarWei Liu <wei.liu@kernel.org>
Link: https://lore.kernel.org/r/20230824080712.30327-3-decui@microsoft.com
parent 08e9d120

arch/x86/hyperv/hv_init.c

+8 −0
Original line number Diff line number Diff line
@@ -476,6 +476,10 @@ void __init hyperv_init(void) 
	/* Hyper-V requires to write guest os id via ghcb in SNP IVM. */

	hv_ghcb_msr_write(HV_X64_MSR_GUEST_OS_ID, guest_id);



	/* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */

	if (hv_isolation_type_tdx())

		goto skip_hypercall_pg_init;



	hv_hypercall_pg = __vmalloc_node_range(PAGE_SIZE, 1, VMALLOC_START,

			VMALLOC_END, GFP_KERNEL, PAGE_KERNEL_ROX,

			VM_FLUSH_RESET_PERMS, NUMA_NO_NODE,
@@ -515,6 +519,7 @@ void __init hyperv_init(void) 
		wrmsrl(HV_X64_MSR_HYPERCALL, hypercall_msr.as_uint64);

	}



skip_hypercall_pg_init:

	/*

	 * hyperv_init() is called before LAPIC is initialized: see

	 * apic_intr_mode_init() -> x86_platform.apic_post_init() and
@@ -642,6 +647,9 @@ bool hv_is_hyperv_initialized(void) 
	if (x86_hyper_type != X86_HYPER_MS_HYPERV)

		return false;



	/* A TDX guest uses the GHCI call rather than hv_hypercall_pg. */

	if (hv_isolation_type_tdx())

		return true;

	/*

	 * Verify that earlier initialization succeeded by checking

	 * that the hypercall page is setup

arch/x86/hyperv/ivm.c

+17 −0
Original line number Diff line number Diff line
@@ -571,3 +571,20 @@ bool hv_isolation_type_tdx(void) 
{

	return static_branch_unlikely(&isolation_type_tdx);

}



#ifdef CONFIG_INTEL_TDX_GUEST



u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2)

{

	struct tdx_hypercall_args args = { };



	args.r10 = control;

	args.rdx = param1;

	args.r8  = param2;



	(void)__tdx_hypercall_ret(&args);



	return args.r11;

}



#endif

arch/x86/include/asm/mshyperv.h

+14 −0
Original line number Diff line number Diff line
@@ -51,6 +51,7 @@ extern union hv_ghcb * __percpu *hv_ghcb_pg; 


extern bool hv_isolation_type_en_snp(void);

bool hv_isolation_type_tdx(void);

u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2);



/*

 * DEFAULT INIT GPAT and SEGMENT LIMIT value in struct VMSA
@@ -63,6 +64,10 @@ int hv_call_deposit_pages(int node, u64 partition_id, u32 num_pages); 
int hv_call_add_logical_proc(int node, u32 lp_index, u32 acpi_id);

int hv_call_create_vp(int node, u64 partition_id, u32 vp_index, u32 flags);



/*

 * If the hypercall involves no input or output parameters, the hypervisor

 * ignores the corresponding GPA pointer.

 */

static inline u64 hv_do_hypercall(u64 control, void *input, void *output)

{

	u64 input_address = input ? virt_to_phys(input) : 0;
@@ -70,6 +75,9 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output) 
	u64 hv_status;



#ifdef CONFIG_X86_64

	if (hv_isolation_type_tdx())

		return hv_tdx_hypercall(control, input_address, output_address);



	if (hv_isolation_type_en_snp()) {

		__asm__ __volatile__("mov %4, %%r8\n"

				     "vmmcall"
@@ -123,6 +131,9 @@ static inline u64 _hv_do_fast_hypercall8(u64 control, u64 input1) 
	u64 hv_status;



#ifdef CONFIG_X86_64

	if (hv_isolation_type_tdx())

		return hv_tdx_hypercall(control, input1, 0);



	if (hv_isolation_type_en_snp()) {

		__asm__ __volatile__(

				"vmmcall"
@@ -174,6 +185,9 @@ static inline u64 _hv_do_fast_hypercall16(u64 control, u64 input1, u64 input2) 
	u64 hv_status;



#ifdef CONFIG_X86_64

	if (hv_isolation_type_tdx())

		return hv_tdx_hypercall(control, input1, input2);



	if (hv_isolation_type_en_snp()) {

		__asm__ __volatile__("mov %4, %%r8\n"

				     "vmmcall"

drivers/hv/hv_common.c

+8 −2
Original line number Diff line number Diff line
@@ -381,10 +381,10 @@ int hv_common_cpu_init(unsigned int cpu) 
			*outputarg = (char *)(*inputarg) + HV_HYP_PAGE_SIZE;

		}



		if (hv_isolation_type_en_snp()) {

		if (hv_isolation_type_en_snp() || hv_isolation_type_tdx()) {

			ret = set_memory_decrypted((unsigned long)*inputarg, pgcount);

			if (ret) {

				kfree(*inputarg);

				/* It may be unsafe to free *inputarg */

				*inputarg = NULL;

				return ret;

			}
@@ -567,3 +567,9 @@ u64 __weak hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_s 
	return HV_STATUS_INVALID_PARAMETER;

}

EXPORT_SYMBOL_GPL(hv_ghcb_hypercall);



u64 __weak hv_tdx_hypercall(u64 control, u64 param1, u64 param2)

{

	return HV_STATUS_INVALID_PARAMETER;

}

EXPORT_SYMBOL_GPL(hv_tdx_hypercall);

include/asm-generic/mshyperv.h

+1 −0
Original line number Diff line number Diff line
@@ -283,6 +283,7 @@ enum hv_isolation_type hv_get_isolation_type(void); 
bool hv_is_isolation_supported(void);

bool hv_isolation_type_snp(void);

u64 hv_ghcb_hypercall(u64 control, void *input, void *output, u32 input_size);

u64 hv_tdx_hypercall(u64 control, u64 param1, u64 param2);

void hyperv_cleanup(void);

bool hv_query_ext_cap(u64 cap_query);

void hv_setup_dma_ops(struct device *dev, bool coherent);