From b59049720dd95021dfe0d9f4e1fa9458a67cfe29 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Tue, 8 Nov 2011 18:23:30 -0600 Subject: KVM: PPC: Paravirtualize SPRG4-7, ESR, PIR, MASn This allows additional registers to be accessed by the guest in PR-mode KVM without trapping. SPRG4-7 are readable from userspace. On booke, KVM will sync these registers when it enters the guest, so that accesses from guest userspace will work. The guest kernel, OTOH, must consistently use either the real registers or the shared area between exits. This also applies to the already-paravirted SPRG3. On non-booke, it's not clear to what extent SPRG4-7 are supported (they're not architected for book3s, but exist on at least some classic chips). They are copied in the get/set regs ioctls, but I do not see any non-booke emulation. I also do not see any syncing with real registers (in PR-mode) including the user-readable SPRG3. This patch should not make that situation any worse. Signed-off-by: Scott Wood Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- arch/powerpc/include/asm/kvm_para.h | 31 +++++++++++++++++++++++++++++-- 1 file changed, 29 insertions(+), 2 deletions(-) (limited to 'arch/powerpc/include/asm/kvm_para.h') diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h index 50533f9adf40..ece70fb36513 100644 --- a/arch/powerpc/include/asm/kvm_para.h +++ b/arch/powerpc/include/asm/kvm_para.h @@ -33,11 +33,35 @@ struct kvm_vcpu_arch_shared { __u64 sprg3; __u64 srr0; __u64 srr1; - __u64 dar; + __u64 dar; /* dear on BookE */ __u64 msr; __u32 dsisr; __u32 int_pending; /* Tells the guest if we have an interrupt */ __u32 sr[16]; + __u32 mas0; + __u32 mas1; + __u64 mas7_3; + __u64 mas2; + __u32 mas4; + __u32 mas6; + __u32 esr; + __u32 pir; + + /* + * SPRG4-7 are user-readable, so we can only keep these consistent + * between the shared area and the real registers when there's an + * intervening exit to KVM. This also applies to SPRG3 on some + * chips. + * + * This suffices for access by guest userspace, since in PR-mode + * KVM, an exit must occur when changing the guest's MSR[PR]. + * If the guest kernel writes to SPRG3-7 via the shared area, it + * must also use the shared area for reading while in kernel space. + */ + __u64 sprg4; + __u64 sprg5; + __u64 sprg6; + __u64 sprg7; }; #define KVM_SC_MAGIC_R0 0x4b564d21 /* "KVM!" */ @@ -47,7 +71,10 @@ struct kvm_vcpu_arch_shared { #define KVM_FEATURE_MAGIC_PAGE 1 -#define KVM_MAGIC_FEAT_SR (1 << 0) +#define KVM_MAGIC_FEAT_SR (1 << 0) + +/* MASn, ESR, PIR, and high SPRGs */ +#define KVM_MAGIC_FEAT_MAS0_TO_SPRG7 (1 << 1) #ifdef __KERNEL__ -- cgit v1.2.3 From 54f65795c8f6e192540756085d738e66ab0917a0 Mon Sep 17 00:00:00 2001 From: Scott Wood Date: Wed, 11 Jan 2012 13:37:35 +0000 Subject: KVM: PPC: refer to paravirt docs in header file Instead of keeping separate copies of struct kvm_vcpu_arch_shared (one in the code, one in the docs) that inevitably fail to be kept in sync (already sr[] is missing from the doc version), just point to the header file as the source of documentation on the contents of the magic page. Signed-off-by: Scott Wood Acked-by: Avi Kivity Signed-off-by: Alexander Graf Signed-off-by: Avi Kivity --- Documentation/virtual/kvm/ppc-pv.txt | 24 ++---------------------- arch/powerpc/include/asm/kvm_para.h | 10 ++++++++++ 2 files changed, 12 insertions(+), 22 deletions(-) (limited to 'arch/powerpc/include/asm/kvm_para.h') diff --git a/Documentation/virtual/kvm/ppc-pv.txt b/Documentation/virtual/kvm/ppc-pv.txt index 2b7ce190cde4..6e7c37050930 100644 --- a/Documentation/virtual/kvm/ppc-pv.txt +++ b/Documentation/virtual/kvm/ppc-pv.txt @@ -81,28 +81,8 @@ additional registers to the magic page. If you add fields to the magic page, also define a new hypercall feature to indicate that the host can give you more registers. Only if the host supports the additional features, make use of them. -The magic page has the following layout as described in -arch/powerpc/include/asm/kvm_para.h: - -struct kvm_vcpu_arch_shared { - __u64 scratch1; - __u64 scratch2; - __u64 scratch3; - __u64 critical; /* Guest may not get interrupts if == r1 */ - __u64 sprg0; - __u64 sprg1; - __u64 sprg2; - __u64 sprg3; - __u64 srr0; - __u64 srr1; - __u64 dar; - __u64 msr; - __u32 dsisr; - __u32 int_pending; /* Tells the guest if we have an interrupt */ -}; - -Additions to the page must only occur at the end. Struct fields are always 32 -or 64 bit aligned, depending on them being 32 or 64 bit wide respectively. +The magic page layout is described by struct kvm_vcpu_arch_shared +in arch/powerpc/include/asm/kvm_para.h. Magic page features =================== diff --git a/arch/powerpc/include/asm/kvm_para.h b/arch/powerpc/include/asm/kvm_para.h index ece70fb36513..7b754e743003 100644 --- a/arch/powerpc/include/asm/kvm_para.h +++ b/arch/powerpc/include/asm/kvm_para.h @@ -22,6 +22,16 @@ #include +/* + * Additions to this struct must only occur at the end, and should be + * accompanied by a KVM_MAGIC_FEAT flag to advertise that they are present + * (albeit not necessarily relevant to the current target hardware platform). + * + * Struct fields are always 32 or 64 bit aligned, depending on them being 32 + * or 64 bit wide respectively. + * + * See Documentation/virtual/kvm/ppc-pv.txt + */ struct kvm_vcpu_arch_shared { __u64 scratch1; __u64 scratch2; -- cgit v1.2.3