lkml.org 
[lkml]   [2020]   [Sep]   [14]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[RFC PATCH 19/35] KVM: SVM: Support port IO operations for an SEV-ES guest
Date
From: Tom Lendacky <thomas.lendacky@amd.com>

For an SEV-ES guest, port IO is performed to a shared (un-encrypted) page
so that both the hypervisor and guest can read or write to it and each
see the contents.

For port IO operations, invoke SEV-ES specific routines that can complete
the operation using common KVM port IO support.

Signed-off-by: Tom Lendacky <thomas.lendacky@amd.com>
---
arch/x86/include/asm/kvm_host.h | 1 +
arch/x86/kvm/svm/sev.c | 9 ++++++
arch/x86/kvm/svm/svm.c | 11 +++++--
arch/x86/kvm/svm/svm.h | 1 +
arch/x86/kvm/x86.c | 51 +++++++++++++++++++++++++++++++++
arch/x86/kvm/x86.h | 3 ++
6 files changed, 73 insertions(+), 3 deletions(-)

diff --git a/arch/x86/include/asm/kvm_host.h b/arch/x86/include/asm/kvm_host.h
index 3e2a3d2a8ba8..7320a9c68a5a 100644
--- a/arch/x86/include/asm/kvm_host.h
+++ b/arch/x86/include/asm/kvm_host.h
@@ -613,6 +613,7 @@ struct kvm_vcpu_arch {

struct kvm_pio_request pio;
void *pio_data;
+ void *guest_ins_data;

u8 event_exit_inst_len;

diff --git a/arch/x86/kvm/svm/sev.c b/arch/x86/kvm/svm/sev.c
index 740b44485f36..da1736d228a6 100644
--- a/arch/x86/kvm/svm/sev.c
+++ b/arch/x86/kvm/svm/sev.c
@@ -1483,3 +1483,12 @@ int sev_handle_vmgexit(struct vcpu_svm *svm)

return ret;
}
+
+int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in)
+{
+ if (!setup_vmgexit_scratch(svm, in, svm->vmcb->control.exit_info_2))
+ return -EINVAL;
+
+ return kvm_sev_es_string_io(&svm->vcpu, size, port,
+ svm->ghcb_sa, svm->ghcb_sa_len, in);
+}
diff --git a/arch/x86/kvm/svm/svm.c b/arch/x86/kvm/svm/svm.c
index 439b0d0e53eb..37c98e85aa62 100644
--- a/arch/x86/kvm/svm/svm.c
+++ b/arch/x86/kvm/svm/svm.c
@@ -1984,11 +1984,16 @@ static int io_interception(struct vcpu_svm *svm)
++svm->vcpu.stat.io_exits;
string = (io_info & SVM_IOIO_STR_MASK) != 0;
in = (io_info & SVM_IOIO_TYPE_MASK) != 0;
- if (string)
- return kvm_emulate_instruction(vcpu, 0);
-
port = io_info >> 16;
size = (io_info & SVM_IOIO_SIZE_MASK) >> SVM_IOIO_SIZE_SHIFT;
+
+ if (string) {
+ if (sev_es_guest(vcpu->kvm))
+ return sev_es_string_io(svm, size, port, in);
+ else
+ return kvm_emulate_instruction(vcpu, 0);
+ }
+
svm->next_rip = svm->vmcb->control.exit_info_2;

return kvm_fast_pio(&svm->vcpu, size, port, in);
diff --git a/arch/x86/kvm/svm/svm.h b/arch/x86/kvm/svm/svm.h
index 8de45462ff4a..9f1c8ed88c79 100644
--- a/arch/x86/kvm/svm/svm.h
+++ b/arch/x86/kvm/svm/svm.h
@@ -564,6 +564,7 @@ void pre_sev_run(struct vcpu_svm *svm, int cpu);
void __init sev_hardware_setup(void);
void sev_hardware_teardown(void);
int sev_handle_vmgexit(struct vcpu_svm *svm);
+int sev_es_string_io(struct vcpu_svm *svm, int size, unsigned int port, int in);

/* VMSA Accessor functions */

diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
index a0070eeeb139..674719d801d2 100644
--- a/arch/x86/kvm/x86.c
+++ b/arch/x86/kvm/x86.c
@@ -10372,6 +10372,10 @@ int kvm_arch_interrupt_allowed(struct kvm_vcpu *vcpu)

unsigned long kvm_get_linear_rip(struct kvm_vcpu *vcpu)
{
+ /* Can't read RIP of an SEV-ES guest, just return 0 */
+ if (vcpu->arch.vmsa_encrypted)
+ return 0;
+
if (is_64_bit_mode(vcpu))
return kvm_rip_read(vcpu);
return (u32)(get_segment_base(vcpu, VCPU_SREG_CS) +
@@ -10768,6 +10772,53 @@ void kvm_fixup_and_inject_pf_error(struct kvm_vcpu *vcpu, gva_t gva, u16 error_c
}
EXPORT_SYMBOL_GPL(kvm_fixup_and_inject_pf_error);

+static int complete_sev_es_emulated_ins(struct kvm_vcpu *vcpu)
+{
+ memcpy(vcpu->arch.guest_ins_data, vcpu->arch.pio_data,
+ vcpu->arch.pio.count * vcpu->arch.pio.size);
+ vcpu->arch.pio.count = 0;
+
+ return 1;
+}
+
+static int kvm_sev_es_outs(struct kvm_vcpu *vcpu, unsigned int size,
+ unsigned int port, void *data, unsigned int count)
+{
+ int ret;
+
+ ret = emulator_pio_out_emulated(vcpu->arch.emulate_ctxt, size, port,
+ data, count);
+ vcpu->arch.pio.count = 0;
+
+ return 0;
+}
+
+static int kvm_sev_es_ins(struct kvm_vcpu *vcpu, unsigned int size,
+ unsigned int port, void *data, unsigned int count)
+{
+ int ret;
+
+ ret = emulator_pio_in_emulated(vcpu->arch.emulate_ctxt, size, port,
+ data, count);
+ if (ret) {
+ vcpu->arch.pio.count = 0;
+ } else {
+ vcpu->arch.guest_ins_data = data;
+ vcpu->arch.complete_userspace_io = complete_sev_es_emulated_ins;
+ }
+
+ return 0;
+}
+
+int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size,
+ unsigned int port, void *data, unsigned int count,
+ int in)
+{
+ return in ? kvm_sev_es_ins(vcpu, size, port, data, count)
+ : kvm_sev_es_outs(vcpu, size, port, data, count);
+}
+EXPORT_SYMBOL_GPL(kvm_sev_es_string_io);
+
static int complete_sev_es_emulated_mmio(struct kvm_vcpu *vcpu)
{
struct kvm_run *run = vcpu->run;
diff --git a/arch/x86/kvm/x86.h b/arch/x86/kvm/x86.h
index ce3b7d3d8631..ae68670f5289 100644
--- a/arch/x86/kvm/x86.h
+++ b/arch/x86/kvm/x86.h
@@ -402,5 +402,8 @@ int kvm_sev_es_mmio_write(struct kvm_vcpu *vcpu, gpa_t src, unsigned int bytes,
void *dst);
int kvm_sev_es_mmio_read(struct kvm_vcpu *vcpu, gpa_t src, unsigned int bytes,
void *dst);
+int kvm_sev_es_string_io(struct kvm_vcpu *vcpu, unsigned int size,
+ unsigned int port, void *data, unsigned int count,
+ int in);

#endif
--
2.28.0
\
 
 \ /
  Last update: 2020-09-14 22:32    [W:0.490 / U:0.764 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site