From ab6315d6b4f9158ee9458d9e9393000943526b2e Mon Sep 17 00:00:00 2001
From: Alexander Boettcher <alexander.boettcher@genode-labs.com>
Date: Mon, 20 May 2019 15:36:47 +0200
Subject: [PATCH] vm_session: add fpu state for x86

Issue #3111
---
 .../base-foc/src/core/vm_session_component.cc |  2 +-
 .../src/core/vm_session_component.cc          |  4 +++-
 repos/base-nova/src/lib/base/vm_session.cc    | 16 +++++++++++--
 .../src/core/spec/x86/vm_session_component.cc |  4 +++-
 repos/base/include/spec/x86/cpu/vm_state.h    | 24 +++++++++++++++++++
 5 files changed, 45 insertions(+), 5 deletions(-)

diff --git a/repos/base-foc/src/core/vm_session_component.cc b/repos/base-foc/src/core/vm_session_component.cc
index 3847c8edb..7e9cbe7fb 100644
--- a/repos/base-foc/src/core/vm_session_component.cc
+++ b/repos/base-foc/src/core/vm_session_component.cc
@@ -87,7 +87,7 @@ Vcpu::Vcpu(Constrained_ram_allocator &ram_alloc,
 {
 	try {
 		/* create ds for vCPU state */
-		_ds_cap = _ram_alloc.alloc(4096, Cache_attribute::CACHED);
+		_ds_cap = _ram_alloc.alloc(0x1000, Cache_attribute::CACHED);
 	} catch (...) {
 		throw;
 	}
diff --git a/repos/base-nova/src/core/vm_session_component.cc b/repos/base-nova/src/core/vm_session_component.cc
index 94aa97693..55f6c91f2 100644
--- a/repos/base-nova/src/core/vm_session_component.cc
+++ b/repos/base-nova/src/core/vm_session_component.cc
@@ -13,6 +13,7 @@
 
 /* Base includes */
 #include <base/cache.h>
+#include <cpu/vm_state.h>
 #include <util/list.h>
 #include <util/flex_iterator.h>
 
@@ -65,7 +66,8 @@ Vm_session_component::Vcpu::Vcpu(Constrained_ram_allocator &ram_alloc,
 
 	try {
 		/* create ds for vCPU state */
-		_ds_cap = _ram_alloc.alloc(4096, Cache_attribute::CACHED);
+		_ds_cap = _ram_alloc.alloc(align_addr(sizeof(Genode::Vm_state), 12),
+		                           Cache_attribute::CACHED);
 	} catch (...) {
 		_cap_alloc.replenish(Cap_quota{CAP_RANGE});
 		cap_map().remove(_sel_sm_ec_sc, CAP_RANGE_LOG2);
diff --git a/repos/base-nova/src/lib/base/vm_session.cc b/repos/base-nova/src/lib/base/vm_session.cc
index 0abeccdf3..fc1a4da3f 100644
--- a/repos/base-nova/src/lib/base/vm_session.cc
+++ b/repos/base-nova/src/lib/base/vm_session.cc
@@ -58,6 +58,12 @@ struct Vcpu {
 			state = Vm_state {};
 			state.exit_reason = exit_reason;
 
+			if (utcb.mtd & Nova::Mtd::FPU) {
+				state.fpu.value([&] (uint8_t *fpu, size_t const) {
+					asm volatile ("fxsave %0" : "=m" (*fpu));
+				});
+			}
+
 			if (utcb.mtd & Nova::Mtd::ACDB) {
 				state.ax.value(utcb.ax);
 				state.cx.value(utcb.cx);
@@ -190,7 +196,6 @@ struct Vcpu {
 				state.tpr_threshold.value(utcb.read_tpr_threshold());
 			}
 
-			/* XXX FPU state missing */
 		}
 
 		static void _write_nova_state(Nova::Utcb &utcb, Vm_state &state)
@@ -389,6 +394,12 @@ struct Vcpu {
 				utcb.write_tpr(state.tpr.value());
 				utcb.write_tpr_threshold(state.tpr_threshold.value());
 			}
+
+			if (state.fpu.valid()) {
+				state.fpu.value([&] (uint8_t *fpu, size_t const) {
+					asm volatile ("fxrstor %0" : : "m" (*fpu));
+				});
+			}
 		}
 
 		void _dispatch()
@@ -655,7 +666,8 @@ struct Vcpu {
 			if (state.qual_primary.valid() || state.qual_secondary.valid())
 				mtd |= Nova::Mtd::QUAL;
 
-			/* XXX FPU missing */
+			if (state.fpu.valid())
+				mtd |= Nova::Mtd::FPU;
 
 			state = Vm_state {};
 
diff --git a/repos/base-sel4/src/core/spec/x86/vm_session_component.cc b/repos/base-sel4/src/core/spec/x86/vm_session_component.cc
index b674e827e..642fd288a 100644
--- a/repos/base-sel4/src/core/spec/x86/vm_session_component.cc
+++ b/repos/base-sel4/src/core/spec/x86/vm_session_component.cc
@@ -13,6 +13,7 @@
 
 /* base includes */
 #include <util/flex_iterator.h>
+#include <cpu/vm_state.h>
 
 /* core includes */
 #include <core_env.h>
@@ -45,7 +46,8 @@ Vm_session_component::Vcpu::Vcpu(Constrained_ram_allocator &ram_alloc,
                                  seL4_Untyped const service)
 :
 	_ram_alloc(ram_alloc),
-	_ds_cap (_ram_alloc.alloc(4096, Cache_attribute::CACHED)),
+	_ds_cap (_ram_alloc.alloc(align_addr(sizeof(Genode::Vm_state), 12),
+	                          Cache_attribute::CACHED)),
 	_vcpu_id(vcpu_id)
 {
 	try {
diff --git a/repos/base/include/spec/x86/cpu/vm_state.h b/repos/base/include/spec/x86/cpu/vm_state.h
index 1018b44ae..291120ad4 100644
--- a/repos/base/include/spec/x86/cpu/vm_state.h
+++ b/repos/base/include/spec/x86/cpu/vm_state.h
@@ -141,6 +141,30 @@ struct Genode::Vm_state
 	Register<uint32_t> tpr_threshold;
 
 	unsigned exit_reason;
+
+	class Fpu {
+		private :
+
+			uint8_t _value[512] { };
+			bool    _valid      { false };
+
+		public:
+
+			bool valid() const { return _valid; }
+			void invalid() { _valid = false; }
+
+			template <typename FUNC>
+			void value(FUNC const &fn) {
+				_valid = true;
+				fn(_value, sizeof(_value));
+			};
+
+			Fpu &operator = (Fpu const &)
+			{
+				_valid = false;
+				return *this;
+			}
+	} fpu __attribute__((aligned(16)));
 };
 
 #endif /* _INCLUDE__SPEC__X86__CPU__VM_STATE_H_ */