[v2,3/5] hv: Add an interface to do nested hypercalls
Commit Message
According to TLFS, in order to communicate to L0 hypervisor there needs
to be an additional bit set in the control register. This communication
is required to perform priviledged instructions which can only be
performed by L0 hypervisor. An example of that could be setting up the
VMBus infrastructure.
Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
---
arch/x86/include/asm/hyperv-tlfs.h | 3 ++-
arch/x86/include/asm/mshyperv.h | 42 +++++++++++++++++++++++++++---
include/asm-generic/hyperv-tlfs.h | 1 +
include/asm-generic/mshyperv.h | 1 +
4 files changed, 42 insertions(+), 5 deletions(-)
Comments
From: Jinank Jain <jinankjain@linux.microsoft.com> Sent: Wednesday, November 2, 2022 9:36 AM
>
> According to TLFS, in order to communicate to L0 hypervisor there needs
> to be an additional bit set in the control register. This communication
> is required to perform priviledged instructions which can only be
> performed by L0 hypervisor. An example of that could be setting up the
> VMBus infrastructure.
>
> Signed-off-by: Jinank Jain <jinankjain@linux.microsoft.com>
> ---
> arch/x86/include/asm/hyperv-tlfs.h | 3 ++-
> arch/x86/include/asm/mshyperv.h | 42 +++++++++++++++++++++++++++---
> include/asm-generic/hyperv-tlfs.h | 1 +
> include/asm-generic/mshyperv.h | 1 +
> 4 files changed, 42 insertions(+), 5 deletions(-)
>
> diff --git a/arch/x86/include/asm/hyperv-tlfs.h b/arch/x86/include/asm/hyperv-tlfs.h
> index 0319091e2019..fd066226f12b 100644
> --- a/arch/x86/include/asm/hyperv-tlfs.h
> +++ b/arch/x86/include/asm/hyperv-tlfs.h
> @@ -380,7 +380,8 @@ struct hv_nested_enlightenments_control {
> __u32 reserved:31;
> } features;
> struct {
> - __u32 reserved;
> + __u32 inter_partition_comm:1;
> + __u32 reserved:31;
> } hypercallControls;
> } __packed;
>
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index 415289757428..451d8c3ab63b 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -74,10 +74,16 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void
> *output)
> return hv_status;
> }
>
> +/* Hypercall to the L0 hypervisor */
> +static inline u64 hv_do_nested_hypercall(u64 control, void *input, void *output)
> +{
> + return hv_do_hypercall(control | HV_HYPERCALL_NESTED, input, output);
> +}
> +
> /* Fast hypercall with 8 bytes of input and no output */
> -static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
> +static inline u64 _hv_do_fast_hypercall8(u64 control, u16 code, u64 input1)
> {
> - u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
> + u64 hv_status;
>
> #ifdef CONFIG_X86_64
> {
> @@ -105,10 +111,24 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
> return hv_status;
> }
>
> +static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
> +{
> + u64 control = (u64)code | HV_HYPERCALL_FAST_BIT;
> +
> + return _hv_do_fast_hypercall8(control, code, input1);
> +}
> +
> +static inline u64 hv_do_fast_nested_hypercall8(u16 code, u64 input1)
> +{
> + u64 control = (u64)code | HV_HYPERCALL_FAST_BIT | HV_HYPERCALL_NESTED;
> +
> + return _hv_do_fast_hypercall8(control, code, input1);
> +}
> +
> /* Fast hypercall with 16 bytes of input */
> -static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
> +static inline u64 _hv_do_fast_hypercall16(u64 control, u16 code, u64 input1, u64 input2)
> {
> - u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
> + u64 hv_status;
>
> #ifdef CONFIG_X86_64
> {
> @@ -139,6 +159,20 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
> return hv_status;
> }
>
> +static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
> +{
> + u64 control = (u64)code | HV_HYPERCALL_FAST_BIT;
> +
> + return _hv_do_fast_hypercall16(control, code, input1, input2);
> +}
> +
> +static inline u64 hv_do_fast_nested_hypercall16(u16 code, u64 input1, u64 input2)
> +{
> + u64 control = (u64)code | HV_HYPERCALL_FAST_BIT | HV_HYPERCALL_NESTED;
> +
> + return _hv_do_fast_hypercall16(control, code, input1, input2);
> +}
> +
> extern struct hv_vp_assist_page **hv_vp_assist_page;
>
> static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
> diff --git a/include/asm-generic/hyperv-tlfs.h b/include/asm-generic/hyperv-tlfs.h
> index fdce7a4cfc6f..c67836dd8468 100644
> --- a/include/asm-generic/hyperv-tlfs.h
> +++ b/include/asm-generic/hyperv-tlfs.h
> @@ -185,6 +185,7 @@ enum HV_GENERIC_SET_FORMAT {
> #define HV_HYPERCALL_VARHEAD_OFFSET 17
> #define HV_HYPERCALL_VARHEAD_MASK GENMASK_ULL(26, 17)
> #define HV_HYPERCALL_RSVD0_MASK GENMASK_ULL(31, 27)
> +#define HV_HYPERCALL_NESTED BIT(31)
Since it is used with a bunch of other u64 values, the above should
probably be BIT_ULL(31).
> #define HV_HYPERCALL_REP_COMP_OFFSET 32
> #define HV_HYPERCALL_REP_COMP_1 BIT_ULL(32)
> #define HV_HYPERCALL_REP_COMP_MASK GENMASK_ULL(43, 32)
> diff --git a/include/asm-generic/mshyperv.h b/include/asm-generic/mshyperv.h
> index bfb9eb9d7215..a2524d96ce2d 100644
> --- a/include/asm-generic/mshyperv.h
> +++ b/include/asm-generic/mshyperv.h
> @@ -53,6 +53,7 @@ extern void * __percpu *hyperv_pcpu_input_arg;
> extern void * __percpu *hyperv_pcpu_output_arg;
>
> extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
> +extern u64 hv_do_nested_hypercall(u64 control, void *inputaddr, void *outputaddr);
Is this needed? hv_do_nested_hypercall() is implemented as a static inline
function in the x86-specific version of mshyperv.h, so this seems duplicative.
But maybe I'm missing something ....
> extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
> extern bool hv_isolation_type_snp(void);
>
> --
> 2.25.1
@@ -380,7 +380,8 @@ struct hv_nested_enlightenments_control {
__u32 reserved:31;
} features;
struct {
- __u32 reserved;
+ __u32 inter_partition_comm:1;
+ __u32 reserved:31;
} hypercallControls;
} __packed;
@@ -74,10 +74,16 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
return hv_status;
}
+/* Hypercall to the L0 hypervisor */
+static inline u64 hv_do_nested_hypercall(u64 control, void *input, void *output)
+{
+ return hv_do_hypercall(control | HV_HYPERCALL_NESTED, input, output);
+}
+
/* Fast hypercall with 8 bytes of input and no output */
-static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
+static inline u64 _hv_do_fast_hypercall8(u64 control, u16 code, u64 input1)
{
- u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
+ u64 hv_status;
#ifdef CONFIG_X86_64
{
@@ -105,10 +111,24 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
return hv_status;
}
+static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
+{
+ u64 control = (u64)code | HV_HYPERCALL_FAST_BIT;
+
+ return _hv_do_fast_hypercall8(control, code, input1);
+}
+
+static inline u64 hv_do_fast_nested_hypercall8(u16 code, u64 input1)
+{
+ u64 control = (u64)code | HV_HYPERCALL_FAST_BIT | HV_HYPERCALL_NESTED;
+
+ return _hv_do_fast_hypercall8(control, code, input1);
+}
+
/* Fast hypercall with 16 bytes of input */
-static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
+static inline u64 _hv_do_fast_hypercall16(u64 control, u16 code, u64 input1, u64 input2)
{
- u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
+ u64 hv_status;
#ifdef CONFIG_X86_64
{
@@ -139,6 +159,20 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
return hv_status;
}
+static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
+{
+ u64 control = (u64)code | HV_HYPERCALL_FAST_BIT;
+
+ return _hv_do_fast_hypercall16(control, code, input1, input2);
+}
+
+static inline u64 hv_do_fast_nested_hypercall16(u16 code, u64 input1, u64 input2)
+{
+ u64 control = (u64)code | HV_HYPERCALL_FAST_BIT | HV_HYPERCALL_NESTED;
+
+ return _hv_do_fast_hypercall16(control, code, input1, input2);
+}
+
extern struct hv_vp_assist_page **hv_vp_assist_page;
static inline struct hv_vp_assist_page *hv_get_vp_assist_page(unsigned int cpu)
@@ -185,6 +185,7 @@ enum HV_GENERIC_SET_FORMAT {
#define HV_HYPERCALL_VARHEAD_OFFSET 17
#define HV_HYPERCALL_VARHEAD_MASK GENMASK_ULL(26, 17)
#define HV_HYPERCALL_RSVD0_MASK GENMASK_ULL(31, 27)
+#define HV_HYPERCALL_NESTED BIT(31)
#define HV_HYPERCALL_REP_COMP_OFFSET 32
#define HV_HYPERCALL_REP_COMP_1 BIT_ULL(32)
#define HV_HYPERCALL_REP_COMP_MASK GENMASK_ULL(43, 32)
@@ -53,6 +53,7 @@ extern void * __percpu *hyperv_pcpu_input_arg;
extern void * __percpu *hyperv_pcpu_output_arg;
extern u64 hv_do_hypercall(u64 control, void *inputaddr, void *outputaddr);
+extern u64 hv_do_nested_hypercall(u64 control, void *inputaddr, void *outputaddr);
extern u64 hv_do_fast_hypercall8(u16 control, u64 input8);
extern bool hv_isolation_type_snp(void);