On 4/14/20 2:03 PM, Mike Stunes wrote:
On Mar 19, 2020, at 2:13 AM, Joerg Roedel <joro@xxxxxxxxxx> wrote:From: Tom Lendacky <thomas.lendacky@xxxxxxx> The runtime handler needs a GHCB per CPU. Set them up and map them unencrypted. Signed-off-by: Tom Lendacky <thomas.lendacky@xxxxxxx> Signed-off-by: Joerg Roedel <jroedel@xxxxxxx> --- arch/x86/include/asm/mem_encrypt.h | 2 ++ arch/x86/kernel/sev-es.c | 28 +++++++++++++++++++++++++++- arch/x86/kernel/traps.c | 3 +++ 3 files changed, 32 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index c17980e8db78..4bf5286310a0 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -197,6 +203,26 @@ static bool __init sev_es_setup_ghcb(void) return true; } +void sev_es_init_ghcbs(void) +{ + int cpu; + + if (!sev_es_active()) + return; + + /* Allocate GHCB pages */ + ghcb_page = __alloc_percpu(sizeof(struct ghcb), PAGE_SIZE); + + /* Initialize per-cpu GHCB pages */ + for_each_possible_cpu(cpu) { + struct ghcb *ghcb = (struct ghcb *)per_cpu_ptr(ghcb_page, cpu); + + set_memory_decrypted((unsigned long)ghcb, + sizeof(*ghcb) >> PAGE_SHIFT); + memset(ghcb, 0, sizeof(*ghcb)); + } +} +set_memory_decrypted needs to check the return value. I see it consistently return ENOMEM. I've traced that back to split_large_page in arch/x86/mm/pat/set_memory.c.
At that point the guest won't be able to communicate with the hypervisor, too. Maybe we should BUG() here to terminate further processing?
Thanks, Tom
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