2022-11-19 03:49:30

by Tianyu Lan

Subject: [RFC PATCH V2 06/18] x86/hyperv: Use vmmcall to implement hvcall in sev-snp enlightened guest

From: Tianyu Lan <[email protected]>

In sev-snp enlightened guest, hvcall needs to use vmmcall to trigger
vmexit and notify hypervisor to handle hypercall request.

Signed-off-by: Tianyu Lan <[email protected]>
---
arch/x86/include/asm/mshyperv.h | 66 ++++++++++++++++++++++-----------
1 file changed, 45 insertions(+), 21 deletions(-)

diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
index 9b8c3f638845..28d5429e33c9 100644
--- a/arch/x86/include/asm/mshyperv.h
+++ b/arch/x86/include/asm/mshyperv.h
@@ -45,16 +45,25 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
u64 hv_status;

#ifdef CONFIG_X86_64
- if (!hv_hypercall_pg)
- return U64_MAX;
+ if (hv_isolation_type_en_snp()) {
+ __asm__ __volatile__("mov %4, %%r8\n"
+ "vmmcall"
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input_address)
+ : "r" (output_address)
+ : "cc", "memory", "r8", "r9", "r10", "r11");
+ } else {
+ if (!hv_hypercall_pg)
+ return U64_MAX;

- __asm__ __volatile__("mov %4, %%r8\n"
- CALL_NOSPEC
- : "=a" (hv_status), ASM_CALL_CONSTRAINT,
- "+c" (control), "+d" (input_address)
- : "r" (output_address),
- THUNK_TARGET(hv_hypercall_pg)
- : "cc", "memory", "r8", "r9", "r10", "r11");
+ __asm__ __volatile__("mov %4, %%r8\n"
+ CALL_NOSPEC
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input_address)
+ : "r" (output_address),
+ THUNK_TARGET(hv_hypercall_pg)
+ : "cc", "memory", "r8", "r9", "r10", "r11");
+ }
#else
u32 input_address_hi = upper_32_bits(input_address);
u32 input_address_lo = lower_32_bits(input_address);
@@ -82,12 +91,18 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;

#ifdef CONFIG_X86_64
- {
+ if (hv_isolation_type_en_snp()) {
+ __asm__ __volatile__(
+ "vmmcall"
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input1)
+ :: "cc", "r8", "r9", "r10", "r11");
+ } else {
__asm__ __volatile__(CALL_NOSPEC
- : "=a" (hv_status), ASM_CALL_CONSTRAINT,
- "+c" (control), "+d" (input1)
- : THUNK_TARGET(hv_hypercall_pg)
- : "cc", "r8", "r9", "r10", "r11");
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input1)
+ : THUNK_TARGET(hv_hypercall_pg)
+ : "cc", "r8", "r9", "r10", "r11");
}
#else
{
@@ -113,14 +128,21 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;

#ifdef CONFIG_X86_64
- {
+ if (hv_isolation_type_en_snp()) {
__asm__ __volatile__("mov %4, %%r8\n"
- CALL_NOSPEC
- : "=a" (hv_status), ASM_CALL_CONSTRAINT,
- "+c" (control), "+d" (input1)
- : "r" (input2),
- THUNK_TARGET(hv_hypercall_pg)
- : "cc", "r8", "r9", "r10", "r11");
+ "vmmcall"
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input1)
+ : "r" (input2)
+ : "cc", "r8", "r9", "r10", "r11");
+ } else {
+ __asm__ __volatile__("mov %4, %%r8\n"
+ CALL_NOSPEC
+ : "=a" (hv_status), ASM_CALL_CONSTRAINT,
+ "+c" (control), "+d" (input1)
+ : "r" (input2),
+ THUNK_TARGET(hv_hypercall_pg)
+ : "cc", "r8", "r9", "r10", "r11");
}
#else
{
@@ -177,6 +199,7 @@ int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu, int vector,
struct hv_interrupt_entry *entry);
int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible);
+int hv_snp_boot_ap(int cpu, unsigned long start_ip);

#ifdef CONFIG_AMD_MEM_ENCRYPT
void hv_ghcb_msr_write(u64 msr, u64 value);
@@ -191,6 +214,7 @@ static inline void hv_ghcb_terminate(unsigned int set, unsigned int reason) {}
#endif

extern bool hv_isolation_type_snp(void);
+extern bool hv_isolation_type_en_snp(void);

static inline bool hv_is_synic_reg(unsigned int reg)
{
--
2.25.1

2022-12-13 17:41:29

by Michael Kelley (LINUX)

Subject: RE: [RFC PATCH V2 06/18] x86/hyperv: Use vmmcall to implement hvcall in sev-snp enlightened guest

From: Tianyu Lan <[email protected]> Sent: Friday, November 18, 2022 7:46 PM
>
> In sev-snp enlightened guest, hvcall needs to use vmmcall to trigger

What does "hvcall" refer to here? Is this a Hyper-V hypercall, or just
a generic hypervisor call?

> vmexit and notify hypervisor to handle hypercall request.
>
> Signed-off-by: Tianyu Lan <[email protected]>
> ---
> arch/x86/include/asm/mshyperv.h | 66 ++++++++++++++++++++++-----------
> 1 file changed, 45 insertions(+), 21 deletions(-)
>
> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
> index 9b8c3f638845..28d5429e33c9 100644
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -45,16 +45,25 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
> u64 hv_status;
>
> #ifdef CONFIG_X86_64
> - if (!hv_hypercall_pg)
> - return U64_MAX;
> + if (hv_isolation_type_en_snp()) {
> + __asm__ __volatile__("mov %4, %%r8\n"
> + "vmmcall"
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input_address)
> + : "r" (output_address)
> + : "cc", "memory", "r8", "r9", "r10", "r11");
> + } else {
> + if (!hv_hypercall_pg)
> + return U64_MAX;
>
> - __asm__ __volatile__("mov %4, %%r8\n"
> - CALL_NOSPEC
> - : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> - "+c" (control), "+d" (input_address)
> - : "r" (output_address),
> - THUNK_TARGET(hv_hypercall_pg)
> - : "cc", "memory", "r8", "r9", "r10", "r11");
> + __asm__ __volatile__("mov %4, %%r8\n"
> + CALL_NOSPEC
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input_address)
> + : "r" (output_address),
> + THUNK_TARGET(hv_hypercall_pg)
> + : "cc", "memory", "r8", "r9", "r10", "r11");
> + }
> #else
> u32 input_address_hi = upper_32_bits(input_address);
> u32 input_address_lo = lower_32_bits(input_address);
> @@ -82,12 +91,18 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
> u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
>
> #ifdef CONFIG_X86_64
> - {
> + if (hv_isolation_type_en_snp()) {
> + __asm__ __volatile__(
> + "vmmcall"
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input1)
> + :: "cc", "r8", "r9", "r10", "r11");
> + } else {
> __asm__ __volatile__(CALL_NOSPEC
> - : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> - "+c" (control), "+d" (input1)
> - : THUNK_TARGET(hv_hypercall_pg)
> - : "cc", "r8", "r9", "r10", "r11");
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input1)
> + : THUNK_TARGET(hv_hypercall_pg)
> + : "cc", "r8", "r9", "r10", "r11");

The above 4 lines appear to just have changes in indentation. Maybe
there's value in having the same indentation as the new code you've
added, so I won't object if you want to keep the changes.

> }
> #else
> {
> @@ -113,14 +128,21 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
> u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
>
> #ifdef CONFIG_X86_64
> - {
> + if (hv_isolation_type_en_snp()) {
> __asm__ __volatile__("mov %4, %%r8\n"
> - CALL_NOSPEC
> - : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> - "+c" (control), "+d" (input1)
> - : "r" (input2),
> - THUNK_TARGET(hv_hypercall_pg)
> - : "cc", "r8", "r9", "r10", "r11");
> + "vmmcall"
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input1)
> + : "r" (input2)
> + : "cc", "r8", "r9", "r10", "r11");
> + } else {
> + __asm__ __volatile__("mov %4, %%r8\n"
> + CALL_NOSPEC
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input1)
> + : "r" (input2),
> + THUNK_TARGET(hv_hypercall_pg)
> + : "cc", "r8", "r9", "r10", "r11");

Same here. Above 5 lines appear to be changes only in indentation.

> }
> #else
> {
> @@ -177,6 +199,7 @@ int hv_map_ioapic_interrupt(int ioapic_id, bool level, int vcpu,
> int vector,
> struct hv_interrupt_entry *entry);
> int hv_unmap_ioapic_interrupt(int ioapic_id, struct hv_interrupt_entry *entry);
> int hv_set_mem_host_visibility(unsigned long addr, int numpages, bool visible);
> +int hv_snp_boot_ap(int cpu, unsigned long start_ip);

This declaration doesn't seem to belong in this patch. It should be
in Patch 13 of the series.

>
> #ifdef CONFIG_AMD_MEM_ENCRYPT
> void hv_ghcb_msr_write(u64 msr, u64 value);
> @@ -191,6 +214,7 @@ static inline void hv_ghcb_terminate(unsigned int set, unsigned
> int reason) {}
> #endif
>
> extern bool hv_isolation_type_snp(void);
> +extern bool hv_isolation_type_en_snp(void);

This declaration seems to be a duplicate that doesn't belong in
this patch.

>
> static inline bool hv_is_synic_reg(unsigned int reg)
> {
> --
> 2.25.1

2022-12-14 16:44:11

by Tianyu Lan

Subject: Re: [RFC PATCH V2 06/18] x86/hyperv: Use vmmcall to implement hvcall in sev-snp enlightened guest

On 12/14/2022 1:19 AM, Michael Kelley (LINUX) wrote:
> From: Tianyu Lan <[email protected]> Sent: Friday, November 18, 2022 7:46 PM
>>
>> In sev-snp enlightened guest, hvcall needs to use vmmcall to trigger
>
> What does "hvcall" refer to here? Is this a Hyper-V hypercall, or just
> a generic hypervisor call?

It's should be Hyper-V hypercall. Will make it accurate in the next
version. Thanks for reminder.

>
>> vmexit and notify hypervisor to handle hypercall request.
>>
>> Signed-off-by: Tianyu Lan <[email protected]>
>> ---
>> arch/x86/include/asm/mshyperv.h | 66 ++++++++++++++++++++++-----------
>> 1 file changed, 45 insertions(+), 21 deletions(-)
>>
>> diff --git a/arch/x86/include/asm/mshyperv.h b/arch/x86/include/asm/mshyperv.h
>> index 9b8c3f638845..28d5429e33c9 100644
>> --- a/arch/x86/include/asm/mshyperv.h
>> +++ b/arch/x86/include/asm/mshyperv.h
>> @@ -45,16 +45,25 @@ static inline u64 hv_do_hypercall(u64 control, void *input, void *output)
>> u64 hv_status;
>>
>> #ifdef CONFIG_X86_64
>> - if (!hv_hypercall_pg)
>> - return U64_MAX;
>> + if (hv_isolation_type_en_snp()) {
>> + __asm__ __volatile__("mov %4, %%r8\n"
>> + "vmmcall"
>> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> + "+c" (control), "+d" (input_address)
>> + : "r" (output_address)
>> + : "cc", "memory", "r8", "r9", "r10", "r11");
>> + } else {
>> + if (!hv_hypercall_pg)
>> + return U64_MAX;
>>
>> - __asm__ __volatile__("mov %4, %%r8\n"
>> - CALL_NOSPEC
>> - : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> - "+c" (control), "+d" (input_address)
>> - : "r" (output_address),
>> - THUNK_TARGET(hv_hypercall_pg)
>> - : "cc", "memory", "r8", "r9", "r10", "r11");
>> + __asm__ __volatile__("mov %4, %%r8\n"
>> + CALL_NOSPEC
>> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> + "+c" (control), "+d" (input_address)
>> + : "r" (output_address),
>> + THUNK_TARGET(hv_hypercall_pg)
>> + : "cc", "memory", "r8", "r9", "r10", "r11");
>> + }
>> #else
>> u32 input_address_hi = upper_32_bits(input_address);
>> u32 input_address_lo = lower_32_bits(input_address);
>> @@ -82,12 +91,18 @@ static inline u64 hv_do_fast_hypercall8(u16 code, u64 input1)
>> u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
>>
>> #ifdef CONFIG_X86_64
>> - {
>> + if (hv_isolation_type_en_snp()) {
>> + __asm__ __volatile__(
>> + "vmmcall"
>> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> + "+c" (control), "+d" (input1)
>> + :: "cc", "r8", "r9", "r10", "r11");
>> + } else {
>> __asm__ __volatile__(CALL_NOSPEC
>> - : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> - "+c" (control), "+d" (input1)
>> - : THUNK_TARGET(hv_hypercall_pg)
>> - : "cc", "r8", "r9", "r10", "r11");
>> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> + "+c" (control), "+d" (input1)
>> + : THUNK_TARGET(hv_hypercall_pg)
>> + : "cc", "r8", "r9", "r10", "r11");
>
> The above 4 lines appear to just have changes in indentation. Maybe
> there's value in having the same indentation as the new code you've
> added, so I won't object if you want to keep the changes.

OK. Will update in the next version.

>
>> }
>> #else
>> {
>> @@ -113,14 +128,21 @@ static inline u64 hv_do_fast_hypercall16(u16 code, u64 input1, u64 input2)
>> u64 hv_status, control = (u64)code | HV_HYPERCALL_FAST_BIT;
>>
>> #ifdef CONFIG_X86_64
>> - {
>> + if (hv_isolation_type_en_snp()) {
>> __asm__ __volatile__("mov %4, %%r8\n"
>> - CALL_NOSPEC
>> - : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> - "+c" (control), "+d" (input1)
>> - : "r" (input2),
>> - THUNK_TARGET(hv_hypercall_pg)
>> - : "cc", "r8", "r9", "r10", "r11");
>> + "vmmcall"
>> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> + "+c" (control), "+d" (input1)
>> + : "r" (input2)
>> + : "cc", "r8", "r9", "r10", "r11");
>> + } else {
>> + __asm__ __volatile__("mov %4, %%r8\n"
>> + CALL_NOSPEC
>> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
>> + "+c" (control), "+d" (input1)
>> + : "r" (input2),
>> + THUNK_TARGET(hv_hypercall_pg)
>> + : "cc", "r8", "r9", "r10", "r11");
>

2023-01-09 07:54:18

by Dexuan Cui

Subject: RE: [RFC PATCH V2 06/18] x86/hyperv: Use vmmcall to implement hvcall in sev-snp enlightened guest

> From: Tianyu Lan <[email protected]>
> Sent: Friday, November 18, 2022 7:46 PM
> --- a/arch/x86/include/asm/mshyperv.h
> +++ b/arch/x86/include/asm/mshyperv.h
> @@ -45,16 +45,25 @@ static inline u64 hv_do_hypercall(u64 control, void
> *input, void *output)
> u64 hv_status;
>
> #ifdef CONFIG_X86_64
> - if (!hv_hypercall_pg)
> - return U64_MAX;
> + if (hv_isolation_type_en_snp()) {
> + __asm__ __volatile__("mov %4, %%r8\n"
> + "vmmcall"
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input_address)
> + : "r" (output_address)
> + : "cc", "memory", "r8", "r9", "r10", "r11");

Add a "return hv_status;" here to avoid chaning the indentation below?

> + } else {
> + if (!hv_hypercall_pg)
> + return U64_MAX;
>
> - __asm__ __volatile__("mov %4, %%r8\n"
> - CALL_NOSPEC
> - : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> - "+c" (control), "+d" (input_address)
> - : "r" (output_address),
> - THUNK_TARGET(hv_hypercall_pg)
> - : "cc", "memory", "r8", "r9", "r10", "r11");
> + __asm__ __volatile__("mov %4, %%r8\n"
> + CALL_NOSPEC
> + : "=a" (hv_status), ASM_CALL_CONSTRAINT,
> + "+c" (control), "+d" (input_address)
> + : "r" (output_address),
> + THUNK_TARGET(hv_hypercall_pg)
> + : "cc", "memory", "r8", "r9", "r10", "r11");
> + }
> #else