lkml.org 
[lkml]   [2022]   [Dec]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [RFC PATCH V2 06/18] x86/hyperv: Use vmmcall to implement hvcall in sev-snp enlightened guest
From
On 12/14/2022 1:19 AM, Michael Kelley (LINUX) wrote:
> From: Tianyu Lan <ltykernel@gmail.com> 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 <tiala@microsoft.com>
>> ---
>> 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");
>

\
 
 \ /
  Last update: 2022-12-14 17:05    [W:0.149 / U:0.384 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site