From: Tianyu Lan <ltykernel@xxxxxxxxx> 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 <tiala@xxxxxxxxxxxxx>
> ---
> 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
