A fully enlightened TDX guest on Hyper-V (i.e. without the paravisor) only
uses the GHCI call rather than hv_hypercall_pg.
In hv_do_hypercall(), Hyper-V requires that the input/output addresses
must have the cc_mask.
Reviewed-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
Reviewed-by: Michael Kelley <mikelley@xxxxxxxxxxxxx>
Signed-off-by: Dexuan Cui <decui@xxxxxxxxxxxxx>
---
Changes in v2:
Included asm/coco.h in arch/x86/include/asm/mshyperv.h to avoid a
gcc warning: "implicit declaration of cc_mkdec"
arch/x86/hyperv/hv_init.c | 8 ++++++++
arch/x86/hyperv/ivm.c | 17 +++++++++++++++++
arch/x86/include/asm/mshyperv.h | 17 +++++++++++++++++
drivers/hv/hv_common.c | 10 ++++++++--
include/asm-generic/mshyperv.h | 1 +
5 files changed, 51 insertions(+), 2 deletions(-)
diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index bcfbcda8b050c..255e02ec467eb 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -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
diff --git a/arch/x86/hyperv/ivm.c b/arch/x86/hyperv/ivm.c
index afdae1a8a1177..6c7598d9e68a3 100644
--- a/arch/x86/hyperv/ivm.c
+++ b/arch/x86/hyperv/ivm.c
@@ -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
diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index e18c6c8f4fba8..24d7f662a8beb 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -5,6 +5,7 @@
#include <linux/types.h>
#include <linux/nmi.h>
#include <linux/msi.h>
+#include <asm/coco.h>
#include <asm/io.h>
#include <asm/hyperv-tlfs.h>
#include <asm/nospec-branch.h>
@@ -51,6 +52,7 @@ 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 +65,10 @@ 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 +76,11 @@ 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,
+ cc_mkdec(input_address),
+ cc_mkdec(output_address));
+
if (hv_isolation_type_en_snp()) {
__asm__ __volatile__("mov %4, %%r8\n"
"vmmcall"
@@ -123,6 +134,9 @@ 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 +188,9 @@ 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"
diff --git a/drivers/hv/hv_common.c b/drivers/hv/hv_common.c
index da3307533f4d7..897bbb96f4118 100644
--- a/drivers/hv/hv_common.c
+++ b/drivers/hv/hv_common.c
@@ -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);
diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
index 82eba2d5fc4cd..f577eff58ea0b 100644
--- a/include/asm-generic/mshyperv.h
+++ b/include/asm-generic/mshyperv.h
@@ -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);
--
2.25.1
