[PATCH v2 2/4] KVM: hyper-v: Collect hypercall params into struct

Siddharth Chandrasekaran
2021-04-12T17:02:43Z

As of now there are 7 parameters (and flags) that are used in various
hyper-v hypercall handlers. There are 6 more input/output parameters
passed from XMM registers which are to be added in an upcoming patch.

To make passing arguments to the handlers more readable, capture all
these parameters into a single structure.

Cc: Alexander Graf <graf@amazon.com>
Cc: Evgeny Iakovlev <eyakovl@amazon.de>
Signed-off-by: Siddharth Chandrasekaran <sidcha@amazon.de>
---
arch/x86/kvm/hyperv.c | 147 +++++++++++++++++++++++-------------------
1 file changed, 79 insertions(+), 68 deletions(-)

diff --git a/arch/x86/kvm/hyperv.c b/arch/x86/kvm/hyperv.c
index f98370a39936..8f6babd1ea0d 100644
--- a/arch/x86/kvm/hyperv.c
+++ b/arch/x86/kvm/hyperv.c
@@ -1623,7 +1623,18 @@ static __always_inline unsigned long *sparse_set_to_vcpu_mask(
return vcpu_bitmap;
}

-static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool ex)
+struct kvm_hv_hcall {
+ u64 param;
+ u64 ingpa;
+ u64 outgpa;
+ u16 code;
+ u16 rep_cnt;
+ u16 rep_idx;
+ bool fast;
+ bool rep;
+};
+
+static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool ex)
{
struct kvm *kvm = vcpu->kvm;
struct kvm_vcpu_hv *hv_vcpu = to_hv_vcpu(vcpu);
@@ -1638,7 +1649,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool
bool all_cpus;

if (!ex) {
- if (unlikely(kvm_read_guest(kvm, ingpa, &flush, sizeof(flush))))
+ if (unlikely(kvm_read_guest(kvm, hc->ingpa, &flush, sizeof(flush))))
return HV_STATUS_INVALID_HYPERCALL_INPUT;

trace_kvm_hv_flush_tlb(flush.processor_mask,
@@ -1657,7 +1668,7 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool
all_cpus = (flush.flags & HV_FLUSH_ALL_PROCESSORS) ||
flush.processor_mask == 0;
} else {
- if (unlikely(kvm_read_guest(kvm, ingpa, &flush_ex,
+ if (unlikely(kvm_read_guest(kvm, hc->ingpa, &flush_ex,
sizeof(flush_ex))))
return HV_STATUS_INVALID_HYPERCALL_INPUT;

@@ -1679,8 +1690,8 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool

if (!all_cpus &&
kvm_read_guest(kvm,
- ingpa + offsetof(struct hv_tlb_flush_ex,
- hv_vp_set.bank_contents),
+ hc->ingpa + offsetof(struct hv_tlb_flush_ex,
+ hv_vp_set.bank_contents),
sparse_banks,
sparse_banks_len))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
@@ -1700,9 +1711,9 @@ static u64 kvm_hv_flush_tlb(struct kvm_vcpu *vcpu, u64 ingpa, u16 rep_cnt, bool
NULL, vcpu_mask, &hv_vcpu->tlb_flush);

ret_success:
- /* We always do full TLB flush, set rep_done = rep_cnt. */
+ /* We always do full TLB flush, set rep_done = hc->rep_cnt. */
return (u64)HV_STATUS_SUCCESS |
- ((u64)rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET);
+ ((u64)hc->rep_cnt << HV_HYPERCALL_REP_COMP_OFFSET);
}

static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector,
@@ -1724,8 +1735,7 @@ static void kvm_send_ipi_to_many(struct kvm *kvm, u32 vector,
}
}

-static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, u64 ingpa, u64 outgpa,
- bool ex, bool fast)
+static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc, bool ex)
{
struct kvm *kvm = vcpu->kvm;
struct hv_send_ipi_ex send_ipi_ex;
@@ -1740,25 +1750,25 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, u64 ingpa, u64 outgpa,
bool all_cpus;

if (!ex) {
- if (!fast) {
- if (unlikely(kvm_read_guest(kvm, ingpa, &send_ipi,
+ if (!hc->fast) {
+ if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi,
sizeof(send_ipi))))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
sparse_banks[0] = send_ipi.cpu_mask;
vector = send_ipi.vector;
} else {
/* 'reserved' part of hv_send_ipi should be 0 */
- if (unlikely(ingpa >> 32 != 0))
+ if (unlikely(hc->ingpa >> 32 != 0))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
- sparse_banks[0] = outgpa;
- vector = (u32)ingpa;
+ sparse_banks[0] = hc->outgpa;
+ vector = (u32)hc->ingpa;
}
all_cpus = false;
valid_bank_mask = BIT_ULL(0);

trace_kvm_hv_send_ipi(vector, sparse_banks[0]);
} else {
- if (unlikely(kvm_read_guest(kvm, ingpa, &send_ipi_ex,
+ if (unlikely(kvm_read_guest(kvm, hc->ingpa, &send_ipi_ex,
sizeof(send_ipi_ex))))
return HV_STATUS_INVALID_HYPERCALL_INPUT;

@@ -1778,8 +1788,8 @@ static u64 kvm_hv_send_ipi(struct kvm_vcpu *vcpu, u64 ingpa, u64 outgpa,

if (!all_cpus &&
kvm_read_guest(kvm,
- ingpa + offsetof(struct hv_send_ipi_ex,
- vp_set.bank_contents),
+ hc->ingpa + offsetof(struct hv_send_ipi_ex,
+ vp_set.bank_contents),
sparse_banks,
sparse_banks_len))
return HV_STATUS_INVALID_HYPERCALL_INPUT;
@@ -1839,20 +1849,21 @@ static int kvm_hv_hypercall_complete_userspace(struct kvm_vcpu *vcpu)
return kvm_hv_hypercall_complete(vcpu, vcpu->run->hyperv.u.hcall.result);
}

-static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)
+static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, struct kvm_hv_hcall *hc)
{
struct kvm_hv *hv = to_kvm_hv(vcpu->kvm);
struct eventfd_ctx *eventfd;

- if (unlikely(!fast)) {
+ if (unlikely(!hc->fast)) {
int ret;
- gpa_t gpa = param;
+ gpa_t gpa = hc->ingpa;

- if ((gpa & (__alignof__(param) - 1)) ||
- offset_in_page(gpa) + sizeof(param) > PAGE_SIZE)
+ if ((gpa & (__alignof__(hc->ingpa) - 1)) ||
+ offset_in_page(gpa) + sizeof(hc->ingpa) > PAGE_SIZE)
return HV_STATUS_INVALID_ALIGNMENT;

- ret = kvm_vcpu_read_guest(vcpu, gpa, &param, sizeof(param));
+ ret = kvm_vcpu_read_guest(vcpu, gpa,
+ &hc->ingpa, sizeof(hc->ingpa));
if (ret < 0)
return HV_STATUS_INVALID_ALIGNMENT;
}
@@ -1862,15 +1873,15 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)
* have no use for it, and in all known usecases it is zero, so just
* report lookup failure if it isn't.
*/
- if (param & 0xffff00000000ULL)
+ if (hc->ingpa & 0xffff00000000ULL)
return HV_STATUS_INVALID_PORT_ID;
/* remaining bits are reserved-zero */
- if (param & ~KVM_HYPERV_CONN_ID_MASK)
+ if (hc->ingpa & ~KVM_HYPERV_CONN_ID_MASK)
return HV_STATUS_INVALID_HYPERCALL_INPUT;

/* the eventfd is protected by vcpu->kvm->srcu, but conn_to_evt isn't */
rcu_read_lock();
- eventfd = idr_find(&hv->conn_to_evt, param);
+ eventfd = idr_find(&hv->conn_to_evt, hc->ingpa);
rcu_read_unlock();
if (!eventfd)
return HV_STATUS_INVALID_PORT_ID;
@@ -1881,9 +1892,8 @@ static u16 kvm_hvcall_signal_event(struct kvm_vcpu *vcpu, bool fast, u64 param)

int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
{
- u64 param, ingpa, outgpa, ret = HV_STATUS_SUCCESS;
- uint16_t code, rep_idx, rep_cnt;
- bool fast, rep;
+ struct kvm_hv_hcall hc;
+ u64 ret = HV_STATUS_SUCCESS;

/*
* hypercall generates UD from non zero cpl and real mode
@@ -1896,104 +1906,105 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)

#ifdef CONFIG_X86_64
if (is_64_bit_mode(vcpu)) {
- param = kvm_rcx_read(vcpu);
- ingpa = kvm_rdx_read(vcpu);
- outgpa = kvm_r8_read(vcpu);
+ hc.param = kvm_rcx_read(vcpu);
+ hc.ingpa = kvm_rdx_read(vcpu);
+ hc.outgpa = kvm_r8_read(vcpu);
} else
#endif
{
- param = ((u64)kvm_rdx_read(vcpu) << 32) |
- (kvm_rax_read(vcpu) & 0xffffffff);
- ingpa = ((u64)kvm_rbx_read(vcpu) << 32) |
- (kvm_rcx_read(vcpu) & 0xffffffff);
- outgpa = ((u64)kvm_rdi_read(vcpu) << 32) |
- (kvm_rsi_read(vcpu) & 0xffffffff);
+ hc.param = ((u64)kvm_rdx_read(vcpu) << 32) |
+ (kvm_rax_read(vcpu) & 0xffffffff);
+ hc.ingpa = ((u64)kvm_rbx_read(vcpu) << 32) |
+ (kvm_rcx_read(vcpu) & 0xffffffff);
+ hc.outgpa = ((u64)kvm_rdi_read(vcpu) << 32) |
+ (kvm_rsi_read(vcpu) & 0xffffffff);
}

- code = param & 0xffff;
- fast = !!(param & HV_HYPERCALL_FAST_BIT);
- rep_cnt = (param >> HV_HYPERCALL_REP_COMP_OFFSET) & 0xfff;
- rep_idx = (param >> HV_HYPERCALL_REP_START_OFFSET) & 0xfff;
- rep = !!(rep_cnt || rep_idx);
+ hc.code = hc.param & 0xffff;
+ hc.fast = !!(hc.param & HV_HYPERCALL_FAST_BIT);
+ hc.rep_cnt = (hc.param >> HV_HYPERCALL_REP_COMP_OFFSET) & 0xfff;
+ hc.rep_idx = (hc.param >> HV_HYPERCALL_REP_START_OFFSET) & 0xfff;
+ hc.rep = !!(hc.rep_cnt || hc.rep_idx);

- trace_kvm_hv_hypercall(code, fast, rep_cnt, rep_idx, ingpa, outgpa);
+ trace_kvm_hv_hypercall(hc.code, hc.fast, hc.rep_cnt, hc.rep_idx,
+ hc.ingpa, hc.outgpa);

- switch (code) {
+ switch (hc.code) {
case HVCALL_NOTIFY_LONG_SPIN_WAIT:
- if (unlikely(rep)) {
+ if (unlikely(hc.rep)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
kvm_vcpu_on_spin(vcpu, true);
break;
case HVCALL_SIGNAL_EVENT:
- if (unlikely(rep)) {
+ if (unlikely(hc.rep)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
- ret = kvm_hvcall_signal_event(vcpu, fast, ingpa);
+ ret = kvm_hvcall_signal_event(vcpu, &hc);
if (ret != HV_STATUS_INVALID_PORT_ID)
break;
fallthrough; /* maybe userspace knows this conn_id */
case HVCALL_POST_MESSAGE:
/* don't bother userspace if it has no way to handle it */
- if (unlikely(rep || !to_hv_synic(vcpu)->active)) {
+ if (unlikely(hc.rep || !to_hv_synic(vcpu)->active)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
vcpu->run->exit_reason = KVM_EXIT_HYPERV;
vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
- vcpu->run->hyperv.u.hcall.input = param;
- vcpu->run->hyperv.u.hcall.params[0] = ingpa;
- vcpu->run->hyperv.u.hcall.params[1] = outgpa;
+ vcpu->run->hyperv.u.hcall.input = hc.param;
+ vcpu->run->hyperv.u.hcall.params[0] = hc.ingpa;
+ vcpu->run->hyperv.u.hcall.params[1] = hc.outgpa;
vcpu->arch.complete_userspace_io =
kvm_hv_hypercall_complete_userspace;
return 0;
case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST:
- if (unlikely(fast || !rep_cnt || rep_idx)) {
+ if (unlikely(hc.fast || !hc.rep_cnt || hc.rep_idx)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
- ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, false);
+ ret = kvm_hv_flush_tlb(vcpu, &hc, false);
break;
case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE:
- if (unlikely(fast || rep)) {
+ if (unlikely(hc.fast || hc.rep)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
- ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, false);
+ ret = kvm_hv_flush_tlb(vcpu, &hc, false);
break;
case HVCALL_FLUSH_VIRTUAL_ADDRESS_LIST_EX:
- if (unlikely(fast || !rep_cnt || rep_idx)) {
+ if (unlikely(hc.fast || !hc.rep_cnt || hc.rep_idx)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
- ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, true);
+ ret = kvm_hv_flush_tlb(vcpu, &hc, true);
break;
case HVCALL_FLUSH_VIRTUAL_ADDRESS_SPACE_EX:
- if (unlikely(fast || rep)) {
+ if (unlikely(hc.fast || hc.rep)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
- ret = kvm_hv_flush_tlb(vcpu, ingpa, rep_cnt, true);
+ ret = kvm_hv_flush_tlb(vcpu, &hc, true);
break;
case HVCALL_SEND_IPI:
- if (unlikely(rep)) {
+ if (unlikely(hc.rep)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
- ret = kvm_hv_send_ipi(vcpu, ingpa, outgpa, false, fast);
+ ret = kvm_hv_send_ipi(vcpu, &hc, false);
break;
case HVCALL_SEND_IPI_EX:
- if (unlikely(fast || rep)) {
+ if (unlikely(hc.fast || hc.rep)) {
ret = HV_STATUS_INVALID_HYPERCALL_INPUT;
break;
}
- ret = kvm_hv_send_ipi(vcpu, ingpa, outgpa, true, false);
+ ret = kvm_hv_send_ipi(vcpu, &hc, true);
break;
case HVCALL_POST_DEBUG_DATA:
case HVCALL_RETRIEVE_DEBUG_DATA:
- if (unlikely(fast)) {
+ if (unlikely(hc.fast)) {
ret = HV_STATUS_INVALID_PARAMETER;
break;
}
@@ -2012,9 +2023,9 @@ int kvm_hv_hypercall(struct kvm_vcpu *vcpu)
}
vcpu->run->exit_reason = KVM_EXIT_HYPERV;
vcpu->run->hyperv.type = KVM_EXIT_HYPERV_HCALL;
- vcpu->run->hyperv.u.hcall.input = param;
- vcpu->run->hyperv.u.hcall.params[0] = ingpa;
- vcpu->run->hyperv.u.hcall.params[1] = outgpa;
+ vcpu->run->hyperv.u.hcall.input = hc.param;
+ vcpu->run->hyperv.u.hcall.params[0] = hc.ingpa;
+ vcpu->run->hyperv.u.hcall.params[1] = hc.outgpa;
vcpu->arch.complete_userspace_io =
kvm_hv_hypercall_complete_userspace;
return 0;
--
2.17.1